McClaren on 27 September 2009
I think it's because the Titans are probably just as power hungery as the Gods. That's why Cronos ate his children and why Zeus kills Kratos.
They need Kratos to help them kill the Gods just so they can reclaim power. Kratos realizes this and decides to get rid of all Gods and Titans.
EDIT: And the Titans probably see Kratos as a huge threat once he's done with the Gods.
