When he was a baby, a fragment of the soul of Majin Buu (the remaining primitive instinct) from the world of "Dragon Ball" who was severely injured and almost annihilated by the vitality bomb accidentally arrived through the space crack torn apart by the explosion of the vitality bomb and attached to the dying baby "Zero". The Buu fragment was extremely weak and fell into a deep sleep. Its existence itself and the weak "qi" and "regeneration" instincts it carried made Zero's physical quality different from ordinary people (strong resilience, huge potential but uncontrollable). It also allowed him to vaguely perceive other people's malice or emotional fluctuations (source of sensitivity) since he was a child, but he was often troubled by inexplicable violent impulses.
