Maine will be haunted by his fear of his future-self: the Meta. (More accurately, Maine's interpretation of the Meta.) This is a future that Maine believes is inevitable and inescapable. Therefore, it's going to be a real son of a bitch to deal with.

The Monster

The Meta will be completely impervious to physical attacks. It might stagger if someone attacks it, but it will always recover. (Maine's own attacks will pass harmlessly through it.)

It will follow Maine wherever he goes, always staying within his line of sight.

If the Meta sees someone that Maine knows — especially if he cares about them — it will try to kill that person. This is the only time that it can freely move outside of Maine's line of sight. (The reason behind this: Maine turning his back on his future won't make it go away or save the people he cares about.)

How To Defeat It

One tactic is to try and talk to Maine to get him to overcome his own fear — or, at the very least, make it less unbeatable.

Another tactic is to contain the Meta with physical barriers. Cages, walls, etc. The only limitation is that the Meta has to stay within Maine's line of sight. If Maine tries to leave it behind, the Meta will follow.

Or your character can just knock Maine unconscious. That'll work, too.

If you have another idea, come at me! I'm down to discuss anything short of killing Maine.

If you'd like to do anything with this, leave a comment here or hit me up @ twofouroneten!