I'm surprised there are people advocating for using Ifrit on this fight. Not only does Contagion give you equal dps potential to Ifrit's slight advantage (because you can time it, for example, when a dreadnought is coming and keep your dots ticking on the main boss while at the same time killing a dreadnought fast -- in my experience a dreadnought dies a few seconds before Bio is about to wear off), but this fight is also a HUGE mana sink. It's long. There's really not much to dodge (besides popping your assigned towers and moving for marks)... a lot of it is just sitting on the boss's butt, so you're not going to naturally regen as much mana as you would on a fight that has 'breaks' of dodging. On the plus side, that also means there's almost no time when you should be using Ruin 2, the exception being if you are popping buffs not on the GCD and want to squeeze in as much damage as possible. I like contagion on this fight because it helps me conserve mana. Ruin spam filler is 79 mp... recasting dots more often? More mp. I haven't even finished this fight yet (50% about) but I can already tell mana conservation is important, and Contagion does help with that.