I think there's 25 possible heals? Arissa, the girl in Daltah, Daltah mines guy, 10 in the castle... there might not be, actually. That said, the main reward from 25 heals requires you to have defeated Magnes already, and you'll find some more pretty soon.
Ulfar appears after 4 enemies (EDIT: Enemy groups, not individual enemies) are defeated or after examining the gravestone in the encounter.