[1.2.398] Minar's Past

But Grendel even being there is based only on "if it's been 100 years".

In game, they keep saying it's been a few hundred years, and apparently they kept up with that during Demon Slayer's and Mercedes new plot lines. (Shakar96's post above)
I think Crawls with Balrog is maybe an ancestor of Dances in Ellin forest. So there is always the chance that Grendel may not even be alive at this point.

Wait, what? What do the security tapes have to do wi-
Ugh. Silly Resistance code. *facepalms*

Anyway, Grendel is basicly VERY VERY old, he must have been somewhere in Ellin forest, or his representant, wich would be that guy at the right barrier stone, wouldn't he?
The actual question is what happend between Ellin Forrest and Present. In that timeline:
The citys on victoria were created.
Grendel and more Fairys besides Ellin appeard.