The Meta is, essentially, Red vs. Blue's Final Boss. He's the show's flashing "YOU ARE DEAD, GAME OVER" screen, the finale at the end of the circus, the hulking shape you most definitely do not want to run into in a dead-end alley on a dark and stormy night. If he hasn't killed you, or attempted to kill you, or given you a look like he wants to kill you, there's a good chance that he just hasn't gotten to you yet and that you're really better off not getting your hopes up.

You think I'm joking. But I'm not. At all. Maine is an ambitious little boy that aggressively goes after his hopes and dreams, and he is fifty different kinds of a-okay with breaking every bone in your body in order to get what he wants. His conscience, the shit in his brain that tells him "this is a bad thing you're doing, and you should feel bad," is more or less non-existent. He's not going to be tossing and turning in bed over anything he's done when he goes to sleep at night.

And that's assuming that he sleeps at all.

Maine is -- crazy. Point blank. He has been been stuffed full of AIs like a Thanksgiving turkey. It doesn't matter that they were forcibly removed from him when the EMP went off at the end of Reconstruction; he is still massively suffering from the disjointing, derailing impact they've had on his mind and sanity. Even now, every breath in his body is pushing him to collect the AI fragments, to piece them together until the Alpha's been recreated, rebuilt from the ground up. It's all he cares about. Period.

It's not necessarily a horrible, awful thing for him to care about, either. If his actions weren't as terribly extreme as they usually tend to be, his end game goal would even be kind of noble, some sort of weird, twisted AI justice. But Maine has been influenced and most likely manipulated by the AI fragments he's spent a good majority of his time with, and as a result, the line that separates human and AI has been significantly blurred.

We have no idea what he was like before he became exclusively known as the Meta. Referred to as the "prodigal son" by the Director, it's likely that he was a highly skilled agent even before he went nutters and turned into Red vs. Blue's version of a rogue SPARTAN. He's a wildcard, someone who would be nice to have on your side, but someone you probably don't want on your side regardless, because he's just as likely to kill you as he is anyone else.

However.

He's not incapable of following orders. As of Revelation, the only person he will even vaguely listen to is Wash, and even then, he's usually carrying out the orders given to him somewhat reluctantly. We see flashes of who Maine was before the AIs every now and then, in the way he occasionally argues or disagrees with Wash, in the way he sometimes hesitates and pauses before doing something. Maine is under there somewhere, buried deep under layers of issues and broken pieces of thought and memory that he can't fix. The only problem is that he can't turn around, anymore.