Boss EPI has hazard AOE located at both ends that deals DOT, and power drains. Her AOE also remove positive buffs on your hero. She is also immune to hazard DOT. This is my 1st attempt on this boss, so I went with a slightly better build. JSGL to counter the hazard power drain effect, Vixen to provide debuff and extra damage, and BB as the damage dealer. Unfortunately, I'm unable to try the other bosses yet. But I'll be back. 😎 I am a FREE TO PLAY player, so I generally work with whatever that is given free.