I dont get it. Was that his actual father in the flashback? Why is he saying he wants to b...

the father asked if the cat wants to be his son hehe

We were thinking about that one for a while.. they said Natsuki's dad died when he was very young, so we think he's one of Natsuki's mom's former boyfriends. He's basically asking Natsuki's permission to become a fatherfigure for him.

oh okay so another lore for natsuki