Born on the same night as Ronja, he was Borka and Undis' only son. As opposed to Ronja, Birk is a bit sensitive and thoughtful but at the same time pragmatic, giving his expression a tinge of cynicism. He becomes drawn to Ronja's cheerful and frank personality.

He gets kidnapped by Mattis which causes problems between Ronja and her father.

[Source: MAL]