I'm genuinely surprised to see comments from two months ago on this anime 😂.
As for all the "pedo" comments, I think people are oversimplifying a very weird fictional premise. I'm not supporting pedophilia in real life at all, but this is a fantasy story with reincarnation as its core concept.
Rudeus isn't walking around in his old body. He was literally reborn and grew up again, and the people around him, including Eris, are also children of that world. It's a morally messy concept, and I completely understand why some people are uncomfortable with it.
That said, it's still fiction. Not every story is meant to reflect or justify real life. If the premise isn't for you, that's completely fair. But calling everyone who enjoys the series a pedophile feels like a huge stretch. It's okay to dislike the story and move on without assuming the worst about the people watching it.
TL;DR: It's fiction. Rudeus was reborn and grew up alongside Eris. He only kept his past life's memories, not his old body or life.
It's just my opinion, guys; he is not the same dude in the same body.