Kratos needs to get heart of bridge keeper of Helheim in order to save Atreus from his illness. He enters Helheim, rips apart everyone who comes across his way to damned of bridge with his Blade of Chaos. Finally, he meets the bridge keeper and takes him down; also tears apart his chest and get his heart. He heads back to Midgard with heart of bridge keeper and hands it over to Freya to treat Atreus for his illness.
Checkout the brutal Bridge keeper boss fight and Kratos journey across Midgard and Helheim.