Fukushuu no Taishi - Level 9999 no Bakumatsu Isekai TenseiThe Level 9999 Otherworldly Warriors From the End of the Edo Period.; 復讐の隊士 - レベル9999の幕末異世界転生

During the end of the Edo Period, the Shinsengumi are suddenly transferred to another world. As they arrive, a guide from the other world, Hangya, appears and tells them, “There’s only one way for you all to return to your former world. Please, defeat the Demon Lord.”This is a tale of the weakest warriors becoming the strongest.