Kenshin is so adopted as Lydia's big brother/friend. Which means she'll try and help take care of him too. She will happily help be his teacher in turn for things he is unfamiliar with. IN particular, I'm hoping maybe down the line he can help her--as she'll have a problem even with fighting monsters. (Monsters in other people's eyes, are often 'friends' in her eyes, thanks to her adventures...)