Kinda stuck, what am i missing?

[SmokeYaSs]

Hi there.
Been gone for a while and im kinda lost.

I seem to be missing a whole area that wasnt there before i took a break.
Looks like an oldschool arena / roman amphitheatre type of place.
Only know it exists from a screenshot in a post by @Hyperduel

I figured that a "secret exit" in a south/eastern forest area map would be most likely.
At least by looking at the screenshot.
But so far i wasnt able to find either that, or figure out what level i might have to simply play again.
Which seemed to be a rather unlikely solution to me so far.
I bet its actually quite simple, and i just kept running past it, but that only gets me so far.

Any help would be much appreciated.

[Adflicto]

4a Agrianna,

[SmokeYaSs]

Thanks a lot, much appreciated.
Was pretty sure i had double-triple checked all possible areas for yet another hidden entrance.
But i guess i mustve somehow missed it afterall.