Monster Arena query

[ImAPacifist_UK]

So I've "captured" all the fiends in calm lands at least once and spoke to the arena guy. I see a chest nearby him (I understand I need a certain item later in the game to open it).

He offered me to battle a special fiend of some sorts, but I backed out to save just in case it's OP and I'll get a game over. So I saved and came back and I don't know how to trigger the battle. I went to the monster page and clicked on calms land, looked at both pages (using d-pad) and I don't see the monster Chimerageist at all.

is there something I'm missing here, I'm confused. I've read various sites saying it should be on the second page but I only see two monsters on there. Marlboro (once) and some other one that I've captured like 2 times.

 

Edit: Ah I realised it was under "area conquest" and not calm lands and on the second page, my bad

Edited July 25, 2020 by ImAPacifist_UK
Found the solution