I'm trying to remember the name of this one non-isekai liteRPG in which the MC was a rock that was turned into a dungeon core by a dragon. And when I say a rock, I seriously mean it previously was just a normal rock and was never human. I mean, as mentioned, it's not isekai. The rock was always just a regular rock, and therefore no reincarnation or anything like that going on.
That said, I tried to search the word "core" and it just wasn't coming up in the search results. So, I'm just not having luck finding this one. Maybe someone else knows what I'm talking about.
(That said, the first book was the only one that was actually any real good. In the 2nd book, where the author decided to give the dungeon core a human form and sexual desires, it started just getting weird and unappealing. Maybe the reason I can't find it is because the author realized it was going downhill fast and just decided to scrap the series.)