d3 Developer Insight: 20 Years of Diablo

[Stan 5,240]

To celebrate 20 years of Diablo, Blizzard sat down with three core team members as they talk how is it to work on Diablo.

Rob Foote, Lead Producer

Q: How long have you been a Diablo fan?

Rob Foote, Lead Producer: I remember playing Diablo with my brothers; we had one computer and the four of us had to play in shifts. We each had our own characters; I remember the first time my brother showed me a Godly Plate of the Whale and I was like, “Oh man, that’s crazy! How did you get that?!” We were playing online, which was so new to us, so exciting and crazy.

Q: What is it about the Diablo series that appeals to you?

Rob Foote: To me, it’s about power and seeing your character develop over time. To struggle through a portion of the game and then go back and find it’s trivial; playing on higher and higher difficulties and watching them get easier. Besides power, there’s loot. Getting a Godly Plate of the Whale or seeing a green item drop for the first time in Diablo II was a thrill. That’s still true in Diablo III; you see a set item drop and think “is this my last piece of Jade Harvester? I sure hope it is!” and then you open it up to see. Once you get those pieces you think “I’m going to raise my difficulty now, because now I’m a lot more powerful.” Building power over time is a fantasy present across the franchise. The tone of Diablo also appeals to me, because it’s so different from other Blizzard games. It’s so dark, and I love horror in games, film, and novels. It’s a great genre.

"Our designers have seemingly infinite ideas, so it’s usually a question of when we can get something done, and what can we deliver for each patch."

Q: Do you remember the first thing you worked on when you joined the Diablo team?

Rob Foote: My first job was as a game tester for Diablo II on the 1.04 patch. Blizzard was a lot smaller back then, and so was our QA team. We basically had to brute-force test Diablo, and if you’ve played D2, it’s very challenging to do because there’s so many different sets and Uniques. One of the craziest bugs we found arose from the set number of facings for each character. We had this checklist where you hold each weapon type and check every single one of the facings, and I thought “We’re never gonna find anything wrong with this; why even run the checklist?” But sure enough, one of the items, in one of the facings, disappeared from my character’s hands.

Q: How did you get started on the team and in your current role?

Rob Foote: I started at Blizzard 16 years ago, and my first job was as a game tester. I also worked on Lord of Destruction as a tester, worked my way up as a producer on World of Warcraft, and then came back as a producer on Diablo III. Now I’m a lead producer on Diablo III, and our job is to manage the schedule and ensure we get stuff done on time so we can publish patches. A lot of the job is about tasking individuals with work that needs to be done, and meeting with designers and asking what they want to accomplish with a feature. We set priorities with the team about the must-haves and the nice-to-haves, then go to work to get stuff done in the best way possible. Our designers have seemingly infinite ideas, so it’s usually a question of when we can get something done, and what can we deliver for each patch.

"(...)loot is what drives the game to me. They’re like presents; you get to open them and they can dramatically change your character."

Q: What is your favorite Diablo item?

Rob Foote: In the first Diablo, it was the Godly Plate of the Whale. In Diablo II, the Stone of Jordan was THE item that consumed us. For Diablo III . . . I’m very unlucky and for the longest time I was trying to find Lut Socks. I needed them for my Earthquake/Leap build, and I waited for the longest time to get them, and it was the last piece to complete my build so I was very happy when I finally got them.

Q: What classes are you playing currently? Do you play Hardcore or Softcore?

Rob Foote: Last season I played a Witch Doctor, and I’ve played a lot of Barbarian. In Diablo II, Barbarian was one of my favorite classes; I also played a lot of Necromancers and Amazons, so in Diablo III I played Witch Doctor, and now with the Necromancer coming out next I’m excited about playing it again. I’ve played the Necromancer internally and it’s a lot of fun. In Season 8 I played my first Hardcore character to 70 and now I think I’ll probably switch back and forth. Hardcore’s a different game; you’re not pushing to the absolute limit, but instead pushing cautiously to the limit with the knowledge that if you die, you lose it all.

Q: What’s it like working on the Diablo team?

Rob Foote: When people ask me what the best part of working at Blizzard is, I always answer, “the people.” Everyone here loves games and our games in particular, so motivation isn’t a factor. People come in every day to make amazing games and that makes our job very rewarding and pretty straightforward. Great ideas can come from anywhere, and our designers regularly have brainstorm sessions with the entire team. It’s all about having great ideas and putting them into the game. Every year, we get better at making Diablo; we trust each other, we listen to each other, and we collaborate. It’s a great place to be and we’re always excited to come in to work.

Q: What do you think is the historical legacy of Diablo? What will people be reading about the series 10–20 years from now?

Rob Foote: I think if, 20 years from now, someone is flipping through a college textbook on game design, and they see the entry on “Action RPG,” the entry would say “see: Diablo.” Anyone who plays that genre and loves it has played Diablo games. I think Diablo satisfies the need to build heroes over time, grow in power, get awesome loot, slay monsters, play with your friends, and share those experiences with others.

Q: What‘s the one thing that would cause Diablo to no longer be Diablo if we removed it from the game?

Rob Foote: Loot. The loot is what drives the game to me. They’re like presents; you get to open them and they can dramatically change your character. When you get a powerful item, you can really feel the increase in your performance; it’s not a 0.4% increase but a 20% increase in damage and you’re just slaying things you used to struggle with in one hit. That’s really satisfying.

"(...)just “fresh meat!” and you’re dead. And you’re like, “Whoa! What just happened?” "

Q: Can you give us an example of something you’re really excited to have worked on?

Rob Foote: There are many moments, but I think the greatest moment for me was when Reaper of Souls shipped. It was obviously a commercial success, but, more importantly, it was also a huge success in the eyes of our players. The community loved it; our family and friends contacted us saying they loved it, the launch went very smoothly, and it was well-received by a lot of people. Second would be shipping Lord of Destruction, because it was the first time I got a credit in the game industry. I still have the instruction manual with my name printed on it.

Q: Can you tell us a little about the Darkening of Tristram (Patch 2.4.3) and how the patch came to be?

Rob Foote: The initial conversation was along the lines of, “we want to do something for the 20th anniversary; what’s the plan?” Initially, we were going to just add the old-school music from Diablo into Diablo III. That evolved into, “what if we could get you to play a representation of Diablo in Diablo III?” That became, “well, one level was pretty easy to do, there’s only 15 more, let’s just do them all.” We had some very passionate people who were dedicated to making it happen, and it kind of snowballed—in a good way—into having all 16 levels, then finding monsters that work within those levels to make it reminiscent of the Diablo I experience. Someone had the idea to run the game in 640x480 resolution, but it wasn’t really feasible—so we created a visual filter instead to get the pixelated look.

Q: What are some of the series’ most difficult and memorable bosses? Any tips?

Rob Foote: The first time you fight the Butcher. Back in the day, there were no spoilers. You didn’t know what was going to happen when you walked into his room, and he instantly killed you. Just “fresh meat!” and you’re dead. And you’re like, “Whoa! What just happened?” I think that’s very memorable.

Q: If you could go back in time and tell the developers of the original Diablo anything, what would it be?

Rob Foote: I don’t think I’d have them change a thing, even things we perceive as flaws. We never consider those things flaws unless, over time, something changes our perspective. You can’t run in Diablo I, which was fine at the time. After Diablo II came out; it let you run, and so obviously we thought, “oh, this is so much better!” But I never thought about that when I was playing D1.

Q: Is it possible to kill Diablo for good?

Rob Foote: In Diablo, the heroes never celebrate. Even when you think you beat him, Diablo is always coming back. Be on your guard. Evil lurks everywhere, and Sanctuary is a dangerous place.

 

Julian Love, Lead VFX Artist

Q: How long have you been a Diablo fan?

Julian Love, Lead VFX Artist: I’d have to go back 20 years to my first year in the industry, 1996. I was working at Sierra Online and our lead programmer brought in a game and said “you’ve got to play this, this is awesome”—it was Diablo. I immediately fell in love. There was a secret pact between the lead engineer, the lead designer, and I—every day we’d just play Diablo together all the time. The producer would show up and be angry at us, or someone would sneak across the hall and say “I died. You’ve got to come help me!” 

Q: What is it about the Diablo series that appeals to you?

Julian Love: Back in 1996 I was playing a lot of Diablo. Some of the guys who played with me wanted to go off on their own and make their own games and we were asking ourselves “what kind of game do you want to make?” and one guy goes, “I want to make a horse racing game!” and I was like, “no way, I want to make a Diablo game!”

And then Diablo II came out and a coworker commented “You know, you show up every day and all you do is talk about Diablo and you know more about it than anyone else. Why aren’t you working there?” So, after six years in the industry, it hit me: “What am I doing? Why am I not working there? I can work there, right?” I quit the next day and I got a job at Blizzard North shortly after.

Q: Do you remember the first thing you worked on when you joined the Diablo team?

Julian Love: What I did was a bit more mundane in nature. We were working on a project that eventually became the engine for Diablo III. Back then you could model a character, but a bunch of steps needed to happen before you could get the character in the game so it could move around. You want to automate as much of it as possible, but back then that wasn’t an industry standard. Nobody had done it. So I worked on the process that lets you turn a polygon into a fully usable character. This process is still in use today; in fact, the Necromancer is being made using the same pipeline I built in 2002.

""Am I going to dig this? Or am I really just done with it?" (...)and just like that I was sucked back into the game again (...)"

Q: How did you get started on the team and in your current role?

Julian Love: I started as a technical artist working on the D3 engine, and about six months in, I noticed people were doing special effects for their characters and—this is going to sound a bit strange—there was a character with a gun. Every time the gun was shot, a little puff of smoke would come out of the barrel. I saw the smoke come out and then shrink down to a point. As you know, smoke does not do that. What I discovered was, many people on the team did their own special effects but no one in particular was passionate about it. They just saw it as something else they had to do.

I really love special effects, so much that at one point I considered working in the film industry. So I built some stuff, everyone loved it and so I said "Seriously, give all of that work to me. Hire someone else to do what I'm doing now and let me do ALL special effects. Nobody gets to do it but me!" because I loved it so much. 

Q: What is your favorite Diablo item?

Julian Love: Two items from Diablo II are my favorites. The first one is Ume's Lament. When I first played Diablo II, the Necromancer completely captured my attention. Playing Hardcore, you have a lot of opportunities to play the same class over and over. I made a few Necromancers and they were terrible. I had no idea what I was doing, so I decided I had to play something else. I picked a Paladin—which was also terrible—but I eventually killed Diablo, and he dropped Ume's Lament. I took it as a sign that I should go back and play more of the Necromancer now that I had a good item for it, so I did—and was much more successful.

Years and years later when I was working at Blizzard North, I had taken a break from the game, so I started again on a fresh character. At that point I had played a lot of Diablo, so I was kind of unsure, like, "Am I going to dig this? Or am I really just done with it?" I walk out of town, the first monster I kill drops a Gull dagger, and just like that I was sucked back into the game again for at least another six months. It was great.

Q: What classes are you playing currently? Do you play Hardcore or Softcore?

Julian Love: Witch Doctor. The variety of builds you can create for Witch Doctor means I've been playing a lot of it. My second class is Monk; he's so fast and responsive it’s hard not to like, but then again, we built him like that. I always play Hardcore and I don't have any Softcore characters. I used to play Softcore exclusively and then I tried Hardcore out of curiosity. Clicking one box changed the whole game. Suddenly everything you do is scarier, and it was awesome. That was it for me. I couldn't go back to Softcore.

"(...)the fact that you can play with just your mouse is crucial to the accessibility the series is known for."

Q: What’s it like working on the Diablo team? What do you do for fun?

Julian Love: There's an old saying for games: "You can't make fun without having fun." I think if you could hear the giggling and laughing at the preposterousness of proposing "let's put over 100 skeletons on the screen for Army of the Dead" and the process of realizing that, you’d understand. No one thinks of these things in isolation, no one sits at their desk alone and comes up with an amazing idea that lights up the world; what happens is we get together and bounce things around and try to one-up each other, and be silly and comical, and propose the most absurd ideas. But it's also very safe to say those things, because there's a lot of trust. Others forgive me for saying something that sounds really off the wall, because they know the next ridiculous, seemingly undoable idea might come from them. Nobody judges the ideas during brainstorms and we let our creativity run wild. We trust that we're coming up with something crazy, but it's always to try and make the game as fun as it can be.

Q: What do you think is the historical legacy of Diablo? What will people be reading about the series 10–20 years from now?

Julian Love: Diablo takes a kind of experience—the fantasy RPG experience—and makes it accessible to everyone. At the time of Diablo’s release, that kind of experience came only to a certain kind of person, and only if you could delve deeply into all the systems, and all the complexities that came with them could you then enjoy the experience. Diablo made it accessible for the rest of us. I can say this with a lot of authority, because I have a relative who I'd say is the quintessential "anti-gamer." He's someone who thinks games are silly; a waste of time. When D3 came out, I convinced him to try it out. After giving him a little direction, he starts clicking, starts killing monsters, and he just lost himself in the game for three hours and had a delightful experience. To me, that's the magic of Diablo.

Q: What‘s the one thing that would cause Diablo to no longer be Diablo if we removed it from the game?

Julian Love: There's a good argument to be made for loot. But I think the important one is preserving the ability to play with one hand. Even though most players will use two hands pretty much all the time, the fact that you can play with just your mouse is crucial to the accessibility the series is known for. If I had to pick a close second, it would be the ability to beat the crap out of so many monsters. Monster-slaying is core to the experience, and if at some point you're not using your skills and items to beat demons into submission, it ceases to be a Diablo game.

"For Army of the Dead, we knew we wanted a long cooldown, flashy spell, and I knew we needed a spell to show people how we were going to bring the Necromancer to the next level."

Q: Can you give us an example of something you’re really excited to have worked on?

Julian Love: I always enjoy trying to figure out new things that will delight our players, and then see their delight when we present it to the world. When we were making the new Witch Doctor skill for Reaper of Souls—Piranhas—the original design was a bit vague, just some kind of summoned debuff, with maybe "some bugs" as a visual. I said, "we need a story here; besides, how will this be different from Locust Swarm? We need something else." You don't want to rehash ideas, and you don't want something that doesn’t fit the class fantasy, but instead something in between, familiar and still new and fresh. Using bugs wasn't good enough, but the idea of animals wasn't bad . . . so what about piranhas? The team latched on to that idea; it was easy to associate it with the Witch Doctor, so we made it. Seeing the reaction as people used that spell for the first time was delightful.

Q: Can you talk about the Necromancer visuals and some of the skills we saw at BlizzCon?

Julian Love: As soon as we decided we were doing the Necromancer, there were skills that made us all say "we can't have a Necromancer without this." Corpse Explosion was at the top of the list. Looking back at Diablo II, the graphics themselves didn't really do the skill justice; the corpses on the ground were iconic, but the notion and the concept of the skill carried it a lot further than visuals did. We have the opportunity to put a strong, clear visual on it, to ensure the skill will feel visceral and fit the fantasy.

When you're working with something with a previous incarnation like this, it's like working with a clay statue that hasn't hardened yet. You're going to touch it and something will change; the question is how.

For Army of the Dead, we knew we wanted a long cooldown, flashy spell, and I knew we needed a spell to show people how we were going to bring the Necromancer to the next level. We gave it a name from a skill which also exists in World of Warcraft, and people just assumed, "oh, okay, they're just going to copy-paste that." Then we got to show it at BlizzCon, and there were literally over one hundred skeletons on the screen. Is this a world record? It has to be. Seeing the reaction from the crowd at BlizzCon was really satisfying. I'm always looking forward to those moments.

Those skills are very grounded and visceral, and that has a lot to do with the visual identity of the Necromancer, who was a very serious, sinister, dark class in Diablo II. We want to make sure we preserve that feeling.

Q: What are some of the series’ most difficult and memorable bosses? Any tips?

Julian Love: I worked on getting patch 1.10 out the door for Diablo II. I showed up, and they were testing Über Diablo, and the guy who was working on it says, “oh, you’re going to LOVE this! It’s almost unbeatable.” He fires up a character outfitted with all rare—yellow—gear, and goes, “look at how HARD this is!” I’m like “You’re kidding, right? Can you get my dual-wielding Barbarian from Battle.net?” A couple days later, I get on my Barbarian, and I say, “okay, watch this,” and I proceed to waste that incarnation of Über Diablo in like 10 seconds. I showed them they were not testing it right, and we started pulling characters from Battle.net to test it, which ended up meaning a 3-month delay to the patch—sorry, everyone!—but in the end the boss was a lot more satisfying.

Q: If you could go back in time and tell the developers of the original Diablo anything, what would it be?

Julian Love: I really like those games for what they are, and it's difficult for me to be critical of anything they've done because that led us to what we have today. A lot of the time, “flaws” are the quirks that make you love a game even more. So, if I had to pick something, it would be a small annoyance; I’d tell them, "don't make gold take inventory space! Put it in its own counter instead" or something. Diablo II is even harder for me, as sometimes I hold it up as the perfect game, but I think if I had to pick something there, I'd say "if you want people to care about resistances, build up to that. Don't let players spend the entire first Act without encountering any poison damage, and then have Andariel wreck them because they had no idea they needed 75% poison resists."

At the same time, these flaws give us stories to tell. The reason we can look back and laugh is because we all got killed by Andariel’s poison damage at one point or another.

Q: Is it possible to kill Diablo for good?

Julian Love: For good? I'm going to give you the smart guy, out-of-the-game-lore answer: you don't want to kill him for good. If we were ever going to make another game and put the Diablo name on it—and I think everyone wants that—we kind of want the Lord of Terror around so you can kill him in it, right? It's OK for an expansion to not have Diablo in it, but every new entry in the series is going to need our titular villain.

 

Joe Shely, Senior Game Designer

Q: How long have you been a Diablo fan?

Joe Shely, Senior Game Designer: I've been a fan since the original Diablo. I played it back in high school and my mom yelled at me for not turning the computer off at bedtime—that spellbook wasn’t going to find itself. I also played tons of Diablo II in college; all those sleepless nights worked out for me, though, because now I get to work on Diablo! 

Q: What is it about the Diablo series that appeals to you?

Joe Shely: The original Diablo was all about getting to the bottom of the dungeon and fighting Diablo. It was a challenge just to make it down there alive and find out what's going on. You have to remember, back then you didn’t have the story that's been developed today, it was just "what is happening under this creepy church?" It was very mysterious and I found it compelling.

In Diablo II, I had a Frost Sorceress and I would Frozen Orb everything; I wanted to get to level 99 and I wanted to beat Diablo on Hell difficulty. I liked putting my points into skills and overcharging skills with +skills on items, playing the item game to maximize my skills, and getting Uniques. I felt like I could always keep progressing my character, and I think that's a strength of Diablo—your character can always get stronger and take on new, harder challenges.

"I think the strongest item I have on any character is probably an Ancient Yang's Recurve with really good rolls."

Q: Do you remember the first thing you worked on when you joined the Diablo team?

Joe Shely: I don't know if I can remember the exact thing, but I probably tuned something that frustrated me as a player. At one point, we had an issue with seeking projectiles that tracked the player being biased towards one direction. It was very good at tracking you in one direction, and very bad at tracking you in the other direction; I realized this playing on my Wizard, so I came in to work the next day and fixed it.

Q: How did you get started on the team and in your current role?

Joe Shely: I began working on Diablo III directly shortly after the original release. I came on to help with Reaper of Souls and got to do a bunch of work on monsters, bosses, systems, Adventure Mode, Greater Rift tuning, and more.

Q: What is your favorite Diablo item?

Joe Shely: I definitely like Cam's Rebuttal. It's not the strongest item—I think the strongest item I have on any character is probably an Ancient Yang's Recurve with really good rolls. In terms of pure power, it's a fantastic item, and I was super excited I got it. But when I look at some of the items that do really interesting things, I really like playing the Crusader and having a window of time where I've got another charge of Falling Sword I don't want to waste. There are conditions under which I won't use it, like if there's only one guy left. Sometimes I try to wait as long as possible before using that second charge to maximize the damage from the Firestarter Rune and Consecration.

"(...)the Diablo legacy is very much still being written. There’s this chase of slaying monsters and getting epic loot and being heroic(...)"

Q: What classes are you playing currently? Do you play Hardcore or Softcore?

Joe Shely: Let’s see . . . I’ve got a Hardcore Wizard in Season 8 and a Demon Hunter non-Seasonal. I also have a Hardcore Crusader I haven’t played in a while, but he’s pretty fun too. I think I play Hardcore for the same reason as many of our players—the stakes are increased, your decisions matter in the combat sense. It’s certainly something I do when I want to sit and only play Diablo III, and really focus on that. I won’t try to do anything else while I’m playing my Hardcore character.

Q: What’s it like working on the Diablo team? What do you do for fun?

Joe Shely: The Diablo team is a great group to work for in many ways; it has its own culture, and it’s a culture that evolved around wanting the best for the game and trying to use our resources and the talent of the team to deliver awesome content for our players. At Blizzard, we have this very strong philosophy of supporting our games for years after their release, so that’s very much our focus on the team, looking at the game week-to-week, month-to-month to figure out what the game needs now, and what’s the best thing to deliver to our fans. I’m very proud of our team-wide brainstorms, where we get everyone in a room and we say “here’s the next piece of content we’re going to do,” like a new zone, and we discuss possibilities. “There are new monsters in this zone; what should they be?”

We get a good sense of what we should do in brainstorms; for example, we’ll start with a rough overview of a new zone, like a cold, shrouded moor; there’s going to be some rocky terrain, and it’s misty . . . so what kind of monsters live there? We look at all those and figure out what can we do, and which ideas resonate most strongly with the team. The advantage of team brainstorming is, when it comes time to make the content, whether it’s modeling a creature, animating it, or adding powers, the people who are doing it know they had input into that feature, which makes everyone more passionate.

Q: What do you think is the historical legacy of Diablo? What will people be reading about the series 10–20 years from now?

Joe Shely: I would hope they would read about it and then go play some Diablo, in whatever form that may be, because I think the Diablo legacy is very much still being written. There’s this chase of slaying monsters and getting epic loot and being heroic, and that thread has tied the franchise together. I would expect to see more of that in the future.

Malthael is a pretty tough boss: he’s got multiple phases,(...) and there’s some stuff that can kill you if you’re not watching.

Q: What‘s the one thing that would cause Diablo to no longer be Diablo if we removed it from the game?

Joe Shely: I think loot is the answer. Slaying monsters, getting epic loot, and using your epic loot to slay more monsters is the core loop of Diablo. You can see this all the way from Diablo I to Diablo III. Look at what spellbooks were in Diablo I; they were a form of epic loot that changed your gameplay. When you consider how legendaries have evolved in Diablo III, you can see how the items in Diablo III very much affect your gameplay in some of those same ways—they can make significant changes to your skills, how they're used, the visual effects of your skills, and gameplay mechanics in quite a similar way to how a spellbook would give you a completely new spell.

Q: Can you give us an example of something you’re really excited to have worked on?

Joe Shely: I’m excited about the changes coming to Greater Rifts in 2.4.3. We've reworked the way we spawn monsters in Greater Rifts, and the most obvious effect is that you're going to see a more consistent and, for some tiles, higher density of monsters—but it's really much more. We want the Greater Rift experience to be as varied as possible, and to have plenty of possibilities to be great. When you go down a floor, you should expect great monsters, surprising tiles, cool pylons, etc. The changes we've done in 2.4.3 are aimed at improving that experience. I think it's going to be a good change for our players.

Q: Can you tell us a little about the Darkening of Tristram (Patch 2.4.3) and how the patch came to be?

Joe Shely: I think one of the things we tried to capture with the anniversary event is this direct connection to the Soulstone and the evil of the Soulstone that ties the franchise together. I think the story of Malthael is a very interesting one; you get to meet the Angiris Council and learn about what's going on with these angels, but it's also nice to have an anchor or touchstone in the Red Soulstone, and that's why we wanted to bring it back for the anniversary event. That's also why we put the additional effort to get the D1 cinematic in there, and make a legendary gem you can put in your helm and really capture what I think was probably one of the most memorable events of Diablo 1—you end up impaling yourself.

Q: What are some of the series’ most difficult and memorable bosses? Any tips?

Joe Shely: The Baal fight in Diablo II: Lord of Destruction is pretty hard if you’re a ranged character. He slows you, and you have to deal with the tight constraints of the room. You’re being thrust directly into the fight. Looking at Diablo III, I think Malthael is a pretty tough boss: he’s got multiple phases, a lot of different mechanics, and there’s some stuff that can kill you if you’re not watching. His clouds can be quite dangerous; the adds he summons are some of the most dangerous monsters you’ll face out in the world, and then his ultimate lightning hands attack does extreme damage, so you really have to be on your toes.

Q: If you could go back in time and tell the developers of the original Diablo anything, what would it be?

Joe Shely: I think there would be a lot of back slapping. I’ve always wanted something to happen with the cow when you click on it, the one outside the entrance to the catacombs. Anything, really. I mean you click him, he moos at you, you think something’s gonna happen. I’d like to think we’ve corrected that in the later games, though.

Editor’s note: We’re not sure what Joe is on about here. 

Q: Is it possible to kill Diablo for good?

Joe Shely: All I can say is, he hasn’t died yet, right? He’s not been permanently vanquished at this point. We’ll have to wait and see

(Source)