Nimi-san has gone against the Shinsengumi. To avoid anymore problems they want to get rid of Serizawa.
have been drained of 
most of their blood.
الجثث قد فقدت معظم دمائها
wurden die Körper der Opfer
mit ihrem eigenen Blut besudelt.
les corps seraient presque entièrement
vidés de leur sang.
erano stati privati di ogni goccia di sangue.
não havia sangue algum nos corpos.