Oooo, very interesting start.
I really like it so far

Oooh very good! Slightly reminsicent of Supernatural in some places. Can't wait for the next chapter!

I loved the story and can't wait for another one featuring these characters. I'd like to find out more about demon hunters in general and then of course about Damon, Kazuya and Cam. I think that for a story so short there's plenty of action and it's really cute how attached Damon's getting to Cam.
I don't really know how four-year-olds act but I think even most adult would be terrified to death in his place so his reaction seemed reaslistic enough.
I'm really curious how Cam - at least, I'm assuming it was Cam - managed to stop the knife.
Great job!

Holy crap that was long! Lol, but awesome! Great intro as I remembered, and I feel so bad for Cam! I hope Kazu-kun could earn more patience later on! He needs it! More than me and that's saying alot! Lol, great job buddy!