Mimir also known as the Smartest Man Alive, is the Norse God of Knowledge and Wisdom and an ally of Kratos and Atreus. He was Odin's advisor and the ambassador of the Aesir Gods until Odin imprisoned him 109 years ago and took his left eye to place it into statue of Thor. He is the tritagonist in God of War (2018).
Personality
Mimir is well-mannered, kind and possesses a cheery if not sarcastic and witty sense of humor. Even in his beheaded state, Mimir tries to make the most of the situation, finding it better than imprisonment and as such he tries to be helpful in any way he can. Mimir often has a wealth of information regarding the deities, monsters, civilizations, the Nine Realms and famous figures of the Norse mythology. Mimir also uses to end most of his phrases with the word "brother", possibly as a form of camaraderie to Kratos and his son Atreus, whom he sometimes calls "little brother" or "lad".
Being a part of the traveling company of Kratos and his son, Mimir becomes something of a balancing force between them, teaching Atreus to use his abilities for good and often advising Kratos to be more open about the truth of his past. To that end, Mimir demonstrates that he is emotionally sensitive and insightful to the potential impact that Kratos's distant attitude towards Atreus could have but respects Kratos's wishes and doesn't inform Atreus himself. He also was the first to notice the dark change in Atreus's behavior once he finally learned of his godly heritage and thus tried to instill the ideals that figures like Tyr stood for, using one's powers with wisdom and for good. When this shift in behavior began to fracture the already tense bond between Atreus and Kratos, Mimir did his best to address the issue carefully.
Quickly, Mimir proved to be a loyal ally and friend to Kratos and his son, helping them find the realm of the giants all the way. Mimir also expressed great concern and worry for Atreus when he began to grow ill after the battles with Magni and Modi. He even begged Baldur to stop attacking Kratos and Atreus, offering to do whatever he wanted but of course, his pleas fell on deaf ears.
Despite his bright personality, Mimir possesses a great deal of anger and resentment towards the Aesir Gods, Odin and Thor in particular. He finds a great majority of them to be hedonistic, paranoid, arrogant, warmongering and the ones to blame for the tragedies the Nine Realms have endured. Before his imprisonment, Mimir did his best to try to bring and make peace between the Realms wherever he could, such as advising Odin to marry Freya to end the conflict between the Aesir and Vanir Gods.
Mimir also blames himself for never managing to do any actual lasting peace when he was Odin's advisor. Whenever he would tell tales of the time he was Odin's advisor, Mimir displays visible remorse and openly admits that he feels guilty. One of the examples was when he openly professed that he deserved Freya's anger and showed visible remorse for what his convincing Freya to marry Odin caused her. He also apologized to Sigrun for being so helpless to save her and the Valkyries.
In contrast to the Aesir Gods, Mimir held Tyr in the highest esteem, believing him to be a great leader who fought for peace, knowledge, and understanding, not for power and control.
Even though he is part of the Norse mythology, Mimir is aware of other mythologies and their pantheons, mentioning in Tyr's vault about the Egyptian gods and of the Greek pantheon in Helheim. With the Greek Gods, he also knows of their demise, which he claimed was deserved. However, he did not know who had dismantled the pantheon until he accompanied Kratos, whom he later learned was Zeus' son and recognized him as the Ghost of Sparta.
Mimir has proven himself to be quite humble, an oddity for a god, as while he takes pride in being the smartest man alive, he admits when there are "gaps" in his knowledge or when dealing with something he has never seen before. He has also shown great respect to Kratos and Atreus's journey to Jotunheim, and asked to be left behind in Tyr's Temple as this moment was important for Kratos and Atreus, thus he didn't want to ruin the moment. The Spartan and his son would come to be fond of Mimir, in that they took him home with them once their journey was over.
Mimir also has a drinking history, having fallen off a mountain in a drunken stupor and suffered severe enough wounds that Eir had to heal him, which he was visibly ashamed of, and noted to have been at least intoxicated when in the presence of giants, implied when he said he never spoke their language while sober.
After imprisoned on the tree for 109 winters, He hold a hatred toward the Aesir Gods and refused to answer their questions as to Baldur. He called Magni and Modi as worthless wankers and dangerous fools.