Ryohei Sasagawa is a boxing obsessed member of the Vongola Family who tends to leap before looking.
Ryohei Sasagawa is the older brother of Kyoko Sasagawa, Tsuna's secret crush, and has been very protective of her since they were kids, even getting a permanent scratch on his face from defending her in a fight as a child. Because of this when we first see him he almost seems more like a threat to Tsuna, being this very powerful boxer who is the older sibling of his dream girl. However he is very upbeat and friendly and wants to pal around with Tsuna, even asking him to join the Boxing team after witnessing his power in his Dying Will mode.
Ryohei lives to the "Extreme"
Ryohei's main motto in life is "Extreme," in fact he even says it to describe almost anything or will shout it out in all of his attacks. He is truly a rare example of power and motivation, for example once he was shot by Dying Will bullet by Reborn, just to turn out that he is always in Dying Will mode, drawing every atom of his power from body.
Varia Ring Battles
Ryohei vs Lussuria
Ryohei finally joined Tsuna's secret world of Mafia battles when the Vongola Rings were handed out and he was chosen to be Tsuna's Sun Guardian. He had to train with Colonello who taught him that he already had all the power he needed, he just never let his body heal so that he could use his powers to their fullest. So the first part of their training was for Ryohei to merely lay on his back under the sun for several days just to let his body repair itself. When he was finished he was chosen to be the first competitor in the battle against the Varia, and faced off against Lussuria. They do battle in a cage with lights that are meant to blind each fighter, however Lussuria is wearing sun glasses that help block out the light. However Ryohei is able to get one punch in on him but he hits his knee which is metallic, damaging his own hand instead. But Ryohei fires off one more attack with everything he has and completely destroys Lussuria's knee. Ryohei is taken away to have his wounds attended to and is absent for the rest of ring battles. However at the end of the battles when Chrome is being held hostage by Belphegor and Viper, and Yamamoto and Gokudera are unable to save her, he comes back and blows away the entire wall to knock Viper and Belphegor out.