Not bad for an opening episode. Lots of stuff to learn from here.
If there's something i could complain is the naming of the characters: it's a bit confusing you almost only refer to them by name. If i were you, i would have a descriptive term for each of them that could be used as synonim. For example, one is big so, aside of his name, you call also "giant".
Also, i found you used an "I" were it should be used. Not sure if it was Kage, but it was a first person perspective i didn't expect.
Keep up the good work ^_^.