Board Thread:General Discussion/@comment-1904000-20130613053934/@comment-1887487-20130621125600

Yeah, but that's when you think of Big Boss as the true evil guy, who he maybe wasn't. More of a chaotic neutral imo.

Theory could be that Kaz may help Snake for revenge only, if he had a separation with BB after the events of TPP, for example because BB  didn't like what Kaz was becoming and went on his own, separate way. Kaz would think of that as a treason, and vow revenge to BB, leading to him working for Campbell and helping Snake, who was supposed to defeat BB. Or maybe he had other plans/benefits with working with Campbell, but really, with this trailer, i feel like something isn't right with Kaz. He really seems to become ravaged by the thought of revenge, and i strongly believe it'll lead him to the "darkside", along with BB, to a certain point.