I'm not a part of the team, but thanks! I'm just a big fan who made the wiki and love this game a lot. I want more people to know about and love this game as well. :)
I assume you mean the "Trald At DOR" event? You can find details and requirements for that event over here: https://summoned-by-accident.fandom.com/wiki/CV_Arena
There is also a separate Trald CG scene once you get the doggo. That one's called "Trald Doggo House Funtime A", which you can find over here: https://summoned-by-accident.fandom.com/wiki/Player%27s_House
Patreon version only for both, obviously, though that will change as of the release tomorrow.