By the start of the series, a.k.a. is the current head of the Vongola family. It is implied that he is becoming too weak to lead the family, and thus accepted Tsuna as the next head of the Vongola Family. However, Xanxus, his adopted son, deemed himself more worthy to become the next boss, so he kidnapped and replaced IX with a fake, who sanctioned the traditional Vongola Tournament. The real IX was placed within the Gola Mosca machine, gradually draining him of his life energy, until he is saved by Tsuna.