Jörmungandr, also known as the World Serpent, is a mythical Jötunn serpent destined to fight Thor come Ragnarök. He becomes an ally of Kratos and Atreus after the pair awaken him from deep slumber within the Lake of Nine.
Personality
Jörmungandr harbors a strong hatred towards the Aesir gods, principally Thor and Odin, for massacring the giants to near extinction. He hates Thor the most (and vice-versa) and both are destined to slay each other during Ragnarök. According to Mimir, the serpent absolutely abhors the statue of Thor as the latter called Thor the fat dobber and getting sick of looking at the statue. This hatred extends to their allies as well, since he becomes enraged and nearly attacks Kratos, Atreus and Mimir when the latter mistakenly tells him that they are Odin's friends in the giants' ancient tongue. Tyr was the only Aesir that earned his respect, as he helped to guard his temple and even responded to the horn in the temple's bridge. He also does not hate Mimir, likely as he is aware that the latter had tried his best to stop Odin from massacring the giants and Mimir understanding his dead tongue.
Jörmungandr feels extremely lonely, due to being both the last living giant in Midgard (following Faye's demise) and one of the very few beings who speak his language. However, the serpent does enjoy talking when he can, being described as a "sparkling conversationalist" by Mimir. Due to this, the serpent also sympathizes with those who have suffered the same loss, which made him more than willing to help Kratos and Atreus.