I think I'm the only one (that I know of anyways) that's thought about this theory. But what if Axel guessed at the danger Roxas would be in if Riku walked free? (Yeah, yeah, big what if) So then Riku needs to go. And since Axel had just finished his fight with Sora and was in no condition to fight Riku, he can send out the Repliku. And, in order to power up the Repliku, Axel has him absorb Zexion's life force or whatever he was absorbing in that scene.
So then Zexion just happened to be a handy power-up instead of a potential threat to Axel's interests directly...
(Of course, it doesn't work, as Riku still leaves Castle Oblivion intact and later fights Roxas, etc, etc.)
Ok, I first saw this information on a youtube video and also checked each voice actor's profile via Google.
Vexen - Derek Stephen Prince (Wiki)
Lexaeus - Dave Boat (no confirmation, but did the voice of Weiss from DoC)
Zexion - Vincent Corazza (his site)
Larxene - Shanelle Gray (no confirmation)
Marluxia - Keith Ferguson (Wiki)
@ KHfanatic4life: Well, IMHO, they're pretty good if you can accept the lighter tone of the story. The mangas don't follow the games' storylines completely, but once you get past that, they're good in of themselves.
Favorite moments:
In COM-
Axel teleporting to avoid Sora's attack during the first fight and getting yelled at by Donald & Goofy for that (Especially funny for me who kept cursing Axel's teleporting during the actual COM game)
Larxene lounging and reading Marquis de Sade
Zexion disguising himself as Sora to confront Riku and using a stick as a Keyblade
