Essentially my problem is that, I put in a female Hero and female Mercenary animation (Hero I added through FEditor in new slots and the Custom Animation NMM while Merc I used FEditor but just pasted over Eirika's animations), which both work perfectly fine, but if you try to promote a female Merc, it will just go to a black screen as soon as the Hero Crest is used, softlocking the game.
Though, if I just make it so the female Mercenary only promotes to a female Hero, the promotion works perfect. Changing the Hero animation to something non-custom also fixes the issue. And while writing this, I actually figured out that making the animation for them the Eirika Lord, which I placed the female Merc animation over, actually works as well.
However... I would still like for there to be branching promotions and use custom animations, cause branching promotions are nice. Is there any known solutions to this?
I only managed to find one thread about this that was on Serenes Forest, and it didn't solve my problem sadly.