Is this one of those mangas that think that because elves live longer they also mature half as fast as humans?
"The life of elves lasts..."
Such expositionary dialogue. And then they add it as actual exposition anyway.
The sense of time isn't tied to the length of your life. There is some change before your brain is fully matured, but it's more or less static after that. Unless you have memory issues.
In the great elven library, he reads human books. Seems the elves don't amount to much.
"Demons don't exist anymore."
Flagging the return of demons, or the one demon party member?
So yes, elves here get demented.
Writing quality isn't exactly excellent, but I'll give it a try since there aren't that many chapters yet.