Yes, it really does warm my heart. Callie is 14, so introducing a kitten was a big risk for us. She's got arthritis and general cantankerousness. Her hiss is bigger than any bite and I've never seen her smack him very hard. She mainly hisses when he invades her space or comes up on her unexpectedly or quickly. When I let Tumble out of his room this morning, I picked up his food dish and opened the blinds. I turned around to find Callie flopped on the floor partially on her back with him over her and they were "boxing". It was a wonderful moment!
Hannah and Tumble have been chasing each other and she's coming around....slowly, but she's getting there. No major skirmishes tonight, which is an improvement. Tumble is just adorable and such a happy little guy despite what he's been through.