Well I don't like making custom adventurers, it feels like cheating. Ydwin is an existing character, and she's stylish.
Just killed the dragon in White Void, whateverhername, with Ydwin the 2-wield rogue/cipher in my group. Her "Ancestral memories" made sure that Aloth always had "Arcane cleansing" to take care of dragon's defensive buff, and Tekehu and Xoti could maintain their buffs and heals. Made this fight quite trivial.
Gotta say, I love Ydwin. )) Why cant I romance her, damnit.
Oh, and about Serafen... not only his subclass sucks. Lategame rogue is a much better damage dealer than a barbarian. Plus, Serafen is a pirate, and I do not approve of piracy.