giyu tomioka (冨岡 義勇 tomioka giyu) is a demon slayer part of the demon slayer corps. He uses the breath of water (水の呼吸 mizu no kokyu) and is a former disciple. the demon slayer mark is an unknown multiplier power boost from being near death and a demon slayer.
.png "鬼滅の刃 無限城編 | 第17巻150話『気づき』ネタバレ | Demon Slayer")
