Reach and defeat Kall Fimbulbringer
Quick answer
Bring 3 Malicious Blood to the Strange Bowl at Aesir Passage, after placing a recovery route and spare kit outside. The three-item offering and Kall target are directly stored in vanilla build 25185596. Kall is consistently reported as a three-phase fight: pierce, fire, frost and lightning are resisted, spirit is ineffective, and blunt or slash are the dependable damage choices. Current game databases disagree on exact total health, so this guide gives no health or time estimate.