Naruto: I Practice Tai Chi, So I Transmigrate to the Ninja World to Practice Tai Chi

[No System + Hyuga Clan + Boy Genius]

The protagonist was frail and often sick as a child, so he learned ancient breathing techniques and practiced Tai Chi to build up his health. After more than ten years of training, he unexpectedly transmigrated into the Hokage world in middle age. There, he slowly grew stronger using the Tai Chi and breathing techniques he had practiced in his previous life, changing the shinobi world.