While I think Mydei adores the Trailblazer, like all Heirs do, I think it would be SO funny if he was kinda jealous and pissy about them because Phainon interacts a ton with them.
He and Phainon have always had a special relationship, even if he isn't always sure where it will lead he knows that much. But Phainon also has a special relationship with the Trailblazer. It's not the same as theirs, but it's special.
And don't get him wrong, at first he was so happy for him. The Trailblazer is a great friend and Phainon really needed someone like them in his life, but soon Mydei starts feeling like throwing himself off a bridge because of the Trailblazer.
Because the Trailblazer matches Phainon's energy in a way Mydei can't, and the Trailblazer even gets him to compete about random things when that was obvious their thing.
At some point Mydei asked Phainon if he wanted to hang out and Phainon told him he couldn't because he was going to be training with the Trailblazer. That had never, and I mean never, happened before. Phainon rarely tells him no, and he never tells him no because he's... Training with someone else. Which is also, by the way, their thing.
He had never felt that Phainon liked anyone romantically, including himself, but with the TB? Yeah, he starts to wonder if he likes them a little. And he is internally fuming.
Mydei is a good, respectable man, above petty feelings or acting upon them. Not to mention feeling entitled to anyone's love... But if he has to see them be so close one more time he's gonna walk into the river of souls and die, or just turn into dust in the spot.
He'd never known jealousy, and it fucking sucks.
Meanwhile chances are the Trailblazer is running a tab on how many times Phainon mentions Mydei.
