Zhongli. The outfit manages to be over the top yet still perfectly appropriate for both combat and civilian scenes, and his rattail gives off just the right level of ancient dragon soul goodness.

Apparently he stole drip from the Heavenly Principals and they've been glassing countries ever since out of envy.

Only one? That's a tough one...

I love dorks and Girls' Frontline has them in spades but I'd rather avoid the most popular characters (too easy) so lets go with SVCh.

It's not my favorite design or unit in the game, heck, she's not even the dorkiest character of the bunch, but something about her pose just makes me smile. I also really like her artist, Nagu, which is a plus.