Raikou was born 10 years after the end of Momoshiki Otsutsuki's attack. He was born to two unknown parents and two unknown siblings. Raikou was born a very cheerful and hard working child, but at around the age of seven, something dramatic happened in his life. Somehow, the memory of Kurama was wiped clean and he came rampaging throughout Konohagakure, firing tailed beast bombs and such. Hundreds of people died, including all of Raikou's family members where he was the sole survivor. He was the only one from the 4th division (a part of the Leaf's branch) to survive and meet the beast face-to-face. Raikou was then left alone in the division and the world, without a place to live, and wandered around like a fish, doing nothing, but seeking help, until a masked man came and helped the child, even training him in a very powerful taijutsu arts to help him seek his one dream and become stronger.
Throughout the years, Raikou has had heavy and deadly visions and problems with himself, such as, seeing things that others cannot see and heavy hallucinations. He tends to go crazy when touched by another person and is normally seen staying isolated and away from people. Raikou is called a "psychopath" because of this despite the fact that he is just heavily tramatized due to Kurama blantly killing his family directly infront of him at such a young age.
Still though, Raikou has trained hard so that he could become one of the greatest ninja in the world and so that he could get revenge for his family and kill the one thing that killed them, the Nine Tailed Beast itsself. Raikou has trained in the categories, taijutsu, kenjutsu, and fuijutsu.