Ryoma Hoshi, the Ultimate Tennis Pro, is a very serious individual. He is calm, composed and mature, despite his appearance, and does not seem to be too affected by the killing game. Due to his prison sentence, he is often very depressed, and sees little to no value in his own life. Because of this, he offers to sacrifice his own life for the sake of saving the others. Even so, he eventually attempts to search for a reason for living, thanks to his classmates' encouragement. 
Ryoma has a very deep and serious voice.