Edge of Madness Guide: Strategy, Abilities, Loot

Wushoolay can cast Chain Lightning and Lightning Cloud. The entire raid can avoid the Chain Lightning by just being behind the boss the whole time, and the Lightning Cloud can be avoided by just moving out of it when it spawns. Other than watching for the Lightning Clouds, just kill the boss. To be safe, ranged can also stay spread to avoid chaining the Chain Lightning if it is cast.

Hazza'rah has a very dangerous ability called Mana Burn that will deal large amounts of damage and chain to players, but it requires Mana to cast. If your Hunters keep Viper Sting up on the boss and a Warlock uses Drain Mana when needed, you can keep him at zero Mana, making him unable to cast it. Hazza'rah will also periodically summon Nightmare Illusion adds. These adds deal very high amounts of damage, but have almost no health. If any DPS attacks them at all, they will die in a couple of hits. Just kill them immediately when you see them. Lastly, the boss will sometimes put the whole raid to Sleep, which is a 6-second sleep that is broken by damage. Just make sure your tanks are topped up with a shield or some HoTs going into it.

Renataki's only important ability is Vanish. This works like a Rogue's Vanish, which just makes him stealthed. You need to find him while he is stealthed by using AoE abilities like Arcane Explosion around the room until you hit him, which will break him back out of stealth. Just keep doing this until you win.

Gri'lek's only important ability is Avatar. Every so often, he will enrage, becoming much larger, and fixating on one player. During Avatar, everyone needs to run away just to play it safe, since he can instantly kill anyone he hits, but once Avatar ends, you can just go back to killing him.