@Cav: 

"...eons after the Hero of Time had beaten Zant himself. "

Mmmm... well-- in an entirely different timeline, yes, but not this one. The Gate of Time wouldn't have just transported him into the future, but into an entirely different part of the Zelda fork in time where Ganon was never in the Twili Realm and thus never conspired with Zant. Twilight Princess follows the Child Link timeline. Perhaps, as a compromisable alternative, Zant could have banished him into this dimension with magic at some point? That way we also wouldn't have to casually throw in something as quintessential as the Gate of Time, either....

So basically Cain would be searching for Midna in a dimension where she's probably doing just fine in the Twilight Realm. He just has no knowledge of it.... which is kind of ironically tragic, but... yeah. You get the picture.

Also, Bellicose seems pretty vague. Attaching a power-up to an emotion.... It's not that it's necessarily OP or anything, buuut... I dunno. I don't have a problem with the whole [url=http://tvtropes.org/pmwiki/pmwiki.php/Main/YouWouldntLikeMeWhenImAngry]"You Wouldn't Like Me When I'm Angry" trope[/url], but coupled with the fact that he seems to be a pretty angry guy.... It's like he's going to be at his all-time high power-wise whenever he actually fights. Instead of making it a power-up, I think maybe a one-time a day/really exhausting sort of move would work better if you don't want to give him something else entirely. 

Perhaps a talent in playing the Twili Harpsicord? Then Cain be all like: [url=http://www.youtube.com/watch?v=GMPIMUuE7yI&t=0m29s]buahahaha[/url]
(Totally kidding btw.) 

In the end, the Bellicose thing is up to you. That's just my two cents on it.