Apologies, I may have missed this if it was already found... but today I decided to record my character entering AMAN Trove in Waughroon Shrine.
For so long now, I always felt like I could see a NPC or monster of some kind in the distance for a split second, but thought it was maybe a glitch or me seeing things. So I grabbed my phone, recorded my entry and played it back frame by frame.
Turns out something is there, it's a floating Ahriman right in the center of the arena. Because it's so far away, it is impossible to make out its name clearly, but it can only be one option. Osschaart from the KSNM30 "Copycat" is the only Ahriman in this zone who comes with its own battlefield. The other one would be Seeker from mission 2-3 who shares its battle with a dragon.
KSNM30s are unrestricted and also have a 30-minute time limit. So in the other zones, it is probably the battlefields Seasons Greetings (Balga's Dais) and Double Dragonians (Horlais Peak), but because these areas spawn your character around a corner from the arena, you will never see the monsters upon entry. There's nothing else to this, I just wanted to share something which has been bugging me since AMAN Trove was implemented.