@Flitx
Why would you assume Frieren is older? They’re both elves and Kraft is physically more mature, so unless it turns out elves reverse age after a certain point, he’s certainly older than her. Much, much older, really, given how she hasn’t changed at all since she met her teacher.
Seems like Kraft was probably a famous hero back in the day; maybe we’ll see some ancient records that obliquely refer to him in the future of this story. I wonder when he heard of this goddess religion and if it had always been around since his youth. It’d make sense for him to get into this religion if it was even older than the elves.