Usui, the Blind Sword, used to be a swordsman working for the shogunate government. However, in a fight against Shishio Makoto, he was blinded. He possesses the Shingan (Eye of Heart), which actually is superhuman hearing that lets him hear another's heartbeat thus enabling him to sense people around him and detect the emotions of others. This ability is so advanced that it appears to be similar to the sonar of a dolphin or bat. Usui and Shishio made a deal upon Usui joining the Juppongatana: That Usui could try to kill Shishio anytime he gets the chance. Saito points out that deep down Usui knows he won't be able to kill Shishio and just boasts about killing him to hide that fact from everyone else. Saito also points out that Shishio knows this too and is just playing along to use Usui. Since Usui can't kill Shishio, he kills people weaker than himself to boost his ego. According to Cho, he is the second strongest of the Juppongatana.

Usui fights using a short spear with a weighted end, the rochin, to attack, and a tortoise shell, the tinbei, as a shield to deflect attacks and block the enemy's vision.

(Source: Wikipedia)