Reborn (リボーン, Ribōn) is the holder of the Yellow pacifier. The titular character, Reborn is an infant hitman belonging to the Vongola Family. As the Vongola IX's most trusted member, he becomes Tsuna's home tutor and trains him into becoming a mafia boss. Since he is an official Vongola member and is only there to train Tsuna, he is not allowed to directly interfere with most of Tsuna's battles, though he is allowed to defend against attacks directed solely at him. His "partner" is a shape-shifting chameleon named Leon (レオン, Reon), who usually sits on Reborn's fedora. The bullets used by Reborn are created inside Leon. When Reborn's student is gradually progressing, Leon's tail falls off, his shape-shifting abilities become unstable, and he is no longer able to create bullets. After Leon creates special items for the student, he returns to normal.
No matter how strong the emotion, Reborn always keeps a straight face and handles many situations as calmly as possible. Reborn often says "Ciao-su" (a mix of the Italian "ciao" and the Japanese "osu", which is a casual male greeting). He randomly appears dressed as "another person" who no one except Tsuna recognizes, and seems to see nothing unusual in any of his own behavior.
In the future, Reborn is mentioned to be dead, and in order to avoid the Negative Seven Rays which Byakuran unleashed in the atmosphere in order to slowly kill the Arcobaleno, the past's Reborn remains in Tsuna's underground base and wears a special suit. He is normally voiced by Neeko in the anime but in his short appearances as an adult, Ken Narita voices him.
Reborn is the baby Home Tutor of Tsunayoshi Sawada and the world's strongest hitman. Whenever he greets someone, he says "Ciaossu," a casual male greeting of Japanese and Italian that combines Ciao and Ossu. He wears a black fedora with a thick Orange stripe running across the sides of the cone. He has black eyes and wears an all black suit with black boots and a red long sleeved polo with a blue necktie underneath. His Adult size form however, wears a yellow long sleeved polo. He is always seen with his pet Chameleon Leon on the brim of his hat, along with his Yellow Arcobaleno Pacifier. Reborn's Dying Will Flame is of the Sun Attribute. Out of all the Arcobaleno, he is the strongest. It was revealed in a flashback that Reborn initially showed anger towards the Arcobaleno curse; however, after a period of exile, he came to accept it, asking Shamal to "erase" his old self. As an Arcobaleno, he remains fairly calm through any situation, even in his "fights" against Colonnello. He did, however, admit to have snapped when Timoteo was revealed to be in Gola Mosca.