Being a descendent of the Matriarch Kaguya Ōtsutsuki, she was raised in an unforgiving clan. You had to be the very best otherwise you were not recognized as a clan member. The Kaguya clan was thought to have been eradicated with the death of her late 2nd cousin Kimimaro Kaguya, but they were wrong. The Kaguya's ultimate destiny is to destroy the shinobi world as we know it, and Mifune grew up believing this twisted ideal as well. She was abused heavily by her father and mother and thrown out as she was seen to be the "problem child" and her elder brother Tetsu Kaguya was tired of being the "perfect child" in the eyes of their parents. Thus, Mifune raised her kids (after having kidnapped them from their father Tekka Uchiha of the Village Hidden in the Leaf) alongside her brother and his wife and children. There, they made their own sect made up of the leftover Kaguya clan members who parted from the main clan. Tetsu did not want to be the head of this clan as he had a wife and children to look after and did not want to bare the weight of more duty, so Mifune naturally took on this role. Mifune is cold and heartless. She never used to be this way until her late husband Tekka had betrayed her when their twin sons Soren and Saion Uchiha were born. The two had an arranged marriage that was a failed attempt at uniting the two clans. However, after the twins were born, Tekka used his sharingan genjutsu to look into some of Mifune's memories to see what kind of person she was as he had his own doubts considering she was part of such a ruthless clan. He saw some bad, and he saw some good. But one memory stood apart from the rest. When Mifune was 16, she was forced to choose between saving herself, or that of her best friend Fouyu Senju as an enemy had captured Fouyu. The enemy was attempting to force Mifune into giving up the fight by making her choose her friend over herself. However, having no guidance by a loving parent or sensei, she chose herself and fled. The enemy killed Fouyu shortly after, and Mifune was running away at top speed crying, hearing each and every agonizing scream that her beloved best friend let out. From there on, she numbed her heart and walked around with only half a soul. It would seem that she never allowed herself to love again after that incident. Mifune lived a life of hatred and seeked vengeance on those who would dare hurt her. After the death of her friend, she became heartless, striking down any who would oppose her. The only people in her life who stuck by her side was her brother and his family. Tekka took his infant sons away from her, and stabbed her in the stomach, attempting to leave her for dead after he saw the darkness in her heart. He took his sons to the Leaf Village and then raised them there until they were only 1 years old. This was when the Uchiha clan was slaughtered by Itachi Uchiha. She sent her brother Tetsu after her twins as she heard from a spy in the Anbu Black Ops that there would be an attack on the Uchiha Clan and did not want her sons to die. Although she did not want them to die, it was for selfish reasons only. She needed an heir to take over the Lead position in the family as her brother Tetsu refused to pass that burden onto his children, the only other potential heirs to their clan. Tetsu kidnaps Soren and Saion Uchiha and takes them back to the Village Hidden in the Mist where their mother Mifune raised them. She was a cold mother who only sought the power of her children. Soren was unlike either of his parents. He is neither cold like his mom, or quiet like his father. He is kind and sensitive in some ways. He seeked a better life than what his mother Mifune could provide. Thus, he deserted the village and his clan, became a rogue ninja, and then ran off into the night to the Village Hidden in The Leaf. This angered Mifune, but she refused to recognize Soren as her son after he left. Now Saion is the only son left under her grasp. He is known to be a bit more like his mother in some ways. Soren is arrogant, calculated, and a little bit cold in some ways. He is too obedient to his mother to step out of line. He also holds some resentment for his slightly younger twin brother Soren for leaving him behind with their abusive mother.