Shining Light of the Dawn - S2.E6

Okita gets angry at Hijikata, who failed to rescue Kondou before he was beheaded. Saito forces Hijikata to stay behind and rest while he takes the front line. The New Government Army attacks the Shougitai, and Harada and Shiranui run into Koudou and a group of Rasetsu coming to seek blood. The two of them manage to kill all of the Rasetsu with silver bullets, but Harada is mortally wounded. Just as Koudou is about to kill Shiranui with a bomb, Harada throws his spear at him, making the bomb backfire on Koudou. Harada and Shiranui are never seen again by the Shinsengumi. Okita overhears some men planning to assassinate Hijikata, and uses his Rasetsu powers to kill them all. Hijikata hears rumor of a white-haired man fighting dozens of men, and he and Chizuru run to the place where Okita is fighting. By the time they reach there, the only thing left is Okita's sword, Okita himself having used up all of his lifespan and disintegrated.