Has he ever lived with a dog before? Does he ever play with other dogs?

Take them to a park so they are on neutral territory. Let them play and walk around for awhile together, then walk them back into your house together. That way Kito doesn't feel that a new dog is invading his space.. he'll rather feel like he's walking in with a friend.

Ack, my foster doggy need to run outside.. I'll continue this post in a few minutes ..