My Faye/Fayetos headcanons:
1) She prophecized Loki’s birth while she was still living in Jotunheim, and this was the main reason why she argued with the giants and left for Midgard
2) She initially saw Kratos as an unavoidable part of her fate and did not trust or even like him, at first. They were forced together by circumstance- during this time, she taught him basic Old Norse, but as they spent more time together, the “lessons” became less of a matter of necessity and more of a way for them to bond
3) I don’t like that Faye and Kratos met at first through a standstill fight because there’s no way a regular mortal could have matched Kratos. I ignore that in canon, and that they knew each other for multiple decades, since Kratos would have noticed that Faye wasn’t aging. I headcanon that they knew each other for about 15 years
4) Faye was a very competent craftswoman, and she decorated their cabin with runes and patterning, which was a huge part of Viking culture anyway
5) Heather is her favorite plant, and she would use heather for making yellow thread and tie it through her hair
6) She had hella scars and tattoos across her body and had a firm belief that the body’s appearance deeply affected a person’s state of mind. As a result, she was very physically active, muscular, and always took care to stay on top of her fighting and hunting skills.
7) She and Kratos never had a “wedding” or were formally married. They had been living together for a few years and fallen in love over that period. When she became pregnant with Atreus, they continued to stay together. I go off 2018 canon and rarely Ragnarok canon, so I personally prefer the idea that they were kindred souls and would have done anything for each other, but that they were not husband and wife.
8) Her and Kratos’s relationship blossomed because they bonded over their shared hardships. She held a lot of hatred for the Norse gods because of their genocide against the giants, and trusted Kratos with this pain. Kratos confided in her about his drowning of Greece and most of the bad stuff he did, but he never told her he killed Calliope and Lysandra- only that they died.
9) Faye was a deeply Justice-driven person and genuinely believed in the power of kindness, but she could be brutal when she needed to be, and always in service to others. Her philosophy hinged on reverent love for life and existence itself, so much so that she would go to severe lengths to protect it.
10) She was a massive goofball and teased Kratos all the time. Secretly, he loved it.
11) She was deeply torn about not telling Kratos the truth about her heritage and held a lot of guilt because, while she loved him, she also continued to be with him out of a sense of duty to her people. She knew that they would have Loki together and that he would be instrumental to saving what remained of the giants, and that caused conflict for her.
12) She loved Atreus more than anything and wanted him to inherit her love for life, despite all the darkness within it. She knew that Atreus would not learn this lesson from Kratos, so she did everything she could to instill her positive and optimistic values in her son.