How come we can find her brother, Bloodhungry, at the Rathskeller Inn, but not Brunhilde herself? Is she just a NPC that appears on special events or something?

She joined the crew of the Freyalise last year. She's a pirate now, like her father. I guess that didn't interest Bloodhungry; he stayed behind to help his mom out. I'm sure Brunhilde will show up again on Keel Hauliday.

She's become a battle challenger, so she'll be available to fight along with the other pirates during that event.

Thanks guys! I must have missed that part last year.