Sora (KHII) vs Kratos (GoWIII)
Sora, at the end of Kingdom Hearts 2. He is in Final Form, with Ultima and Fenrir. Additionally, he retains all of his powers and abilities from the first Kingdom Hearts, but it is assumed that "stop" will not work against Kratos.
vs
Kratos, end of GoWIII (
Spoiler:).
Before he dies, of course.
The battle takes place in The World That Never Was.
Now, I haven't actually played the third God of War. So if Kratos obtains anything resembling god-like powers, take that out.