|“||Some people value their privacy. Best don't judge, brother||”|
–Mimir to Kratos
Mimir is the Norse God of Knowledge and Wisdom and an ally of Kratos and Atreus in God of War. He was Odin's advisor and ambassador of the Gods, until Odin imprisoned him 109 years ago.
When he is first found, Mimir is shown to be in a tree. He has two small horns on his head and a growing, grey beard. He eventually is decapitated and brought back to life, though he still looks the same.
Mimir was imprisoned by Odin before the events of the game. Up until he met Kratos, he was tortured by Odin himself on a near daily basis. Baldur confronts him and attempts to bribe him with freedom in exchange for revealing Kratos and the boy's whereabouts, but Mimir was unable to locate them due to a concealing rune placed on the pair by a witch.
Almost immediately after Baldur leaves, Kratos and Atreus reveal themselves to Mimir. Mimir introduces himself to the two. When Atreus describes their journey to the tallest peak in all the Nine Realms, Mimir states that Atreus is mistaken about choosing Midgard's tallest peak, as the tallest peak in all of the realms is in Jötunheim. He also reveals that he can open the last known gate to the realm.
In return, Mimir asks Kratos to cut off his head, explaining that after over 100 years of torture, his current state is not living at all. Kratos agrees to do so. Atreus cannot bear to watch and leaves, and when he does so, Mimir tells Kratos he must reveal his past to Atreus and the longer he waits, the more likely Atreus will grow resentful of him. Kratos then cuts off his head, temporarily killing him.
His lifeless head is brought over to Freya's home, where she revives it. It is quickly revealed that the two have a bad relationship. Mimir also reveals Freya's identity, and in return learns that she never revealed it to Atreus and Kratos. Freya warns Kratos that Odin's wrath will be coming quickly now that Kratos has Mimir, and Kratos storms out of Freya's home.
- Mimir and Helios were the only gods that Kratos decapitated. Also, both of them had a use for him.
- Mimir's imprisonment and initial death is similar to Prometheus's situation, as both were imprisoned by the ruling god of their land for a supposed crime, and both were mercy killed.
- Mimir is the only one of Kratos's victims to have been resurrected.
- Mimir figured out Kratos was Greek due to him saying Athena's name, later he finds that he was the son of Zeus which explained a lot to him, soon exclaiming Kratos is The Ghost of Sparta.
- Mimir said that he knew that one day the Greek gods would fall, implying he knew of the Olympians' demise, however he never knew who did it until Kratos took him along.
- Mimir is the only god who is genuinely helping Kratos in his journeys, without even trying to use him on some purpose, leading to eventual betrayal, going so far as calling him "brother", Ares, Athena, and the Olympians merely used him as a killing vessel for their own personal gain.
- His Greek equivalent is Athena and Mnemosyne. He replaced Athena as Kratos' personal ally in wisdom and knowledge from this point onward.