Ever since I first ran into them, the Malta Group have been far and away my favorite enemy group in the game. The way Indigo and Crimson introduce you to them is fantastic. I hadn't heard about them at all and I was like, "Who ARE these guys?! They're super tough and mysterious!", and I was hooked from that point on. I love the super-tech, black-ops secret society vibe they have going, I love their mechs, I love that they present even max level characters with a challenge if you aren't paying attention, that you have to plan each fight with them at least a little bit ahead of time or they will rapidly screw you over. I love the writing for their storylines and the feeling that you're delving into the shadowy underpinnings of the superhero world. No other enemies in the game come close to how awesome and fun they are and how satisfying it is to beat their bigoted secret-agent asses.