The current head of the Vongola crime family. His age is unknown,but it is implied that he is becoming too weak to lead the family,which is why he searches for his successor. It is revealed that he has been plagued with problems concerning his legs, thereby limiting his mobility.He accepted Iemitsu's son, Tsuna, as the next head of the Vongola Family, but a fake IX that replaced him decided that Xanxus was more worthy to become the next boss. Not realizing this IX was a fake, Iemitsu argued, wanting Tsuna to become the 10th boss. Thus, the fakeIX sanctioned the traditional Vongola battle; those who wield the same ring will have a one-on-one battle. The real IX was kidnapped by Xanxus, who had placed him within Gola Mosca, draining him of his life energy. When Tsuna sliced Gola Mosca's armor in half, the IX was able to use his flame to show Tsuna his past;the IX used to visit Tsuna when he was just a child. In the future, he has been unaccounted for since the Millefiore Family raided the main Vongola headquarters. During Tsuna's training within Hibari's spiked ball, he appears in a vision with the other Vongola heads and is shown with a flaming scepter,his signature Dying Will Flame weapon. Seeing him in the vision causes Tsuna to believe that he may be dead. Like Tsuna and the first, the IX also knows how to use the Zero Point Breakthrough, using it to stop Xanxus' rebellion during the Cradle incident. The Vongola IX's stamp is the Dying Will Flame; he marks documents with his flame, proving they are official.

Nowadays, the mafia world is ruled by Italy's strongest family, the Vongola. Vongola's current head, ninth in the row, is an old man ready for retirement. But before he can hand down his position, he needs help from a professional Hitman to prepare the next generation Boss for ruling over Vongola and the mafia world itself. 
Sawada Tsunayoshi is just your ordinary teenage boy who attends Junior High and sucks at it. He is unpopular, has no friends, and is desperately in love with a girl from his class. But his life takes an extraordinary turn when Tsunayoshi meets Reborn, an infamous hitman, who the ninth boss of Vongola has sent to train Tsunayoshi for his upcoming title. 
(Source: Katekyo Hitman Reborn! FC)

[Wiki (jp)](https://ja.wikipedia.org/wiki/屋良有作)

Sawada Tsunayoshi is regular boy who has never excelled in sports, school or social life, thus being named "No Good Tsuna". Everyday, he leads just a normal life, living with his mother, while his father is away for work. But the thing Tsunayoshi doesn't know is that his family is actual lineage of the great Mafia Boss, the first head of Vongola, Giotto. 
Because of the Sawada history, Tsuna has been chosen to become tenth head of the Vongola family, an infamous Italian mafia family which rules the Mafia world. To become worthy of the title, Tsuna is being aided by professional hitman and infant, Reborn, who takes the role of Tsunayoshi's mafia tutor. 
(Source: Katekyo Hitman Reborn! FC)
 
Note: Chapter count includes two extra collections of short chapters published in volume 42

Timoteo