Sleepy Eyes Of Death 6: Sword Of Satan 1965 Story by Renzaburô Shibata, screenplay by Seiji Hoshikawa, directed by Kimiyoshi Yasuda.
Nemuri Kyoshiro finds himself in the middle of the fall of the Iwashiro Clan. A woman offers herself for some money and he goes along with her. Instead of sleeping with her Nemuri questions her on her choice to raise money. Turns out her son is the heir to the Iwashiro Clan. Trouble is her son's not in the dead Lord's house and an Inspector from the Shogun is coming to see the boy. If there's no heir the clan would be disbanded.
Nemuri is annoyed by her, he leaves her with a gold piece and some harsh words, the next morning he finds out she's killed herself. He vows to help her son, the boy is living with a carpenter and that's what he wants to be. The clan has other ideas and kidnaps the boy with the help of a woman called Orin who's trying to get revenge on Nemuri for killing her brother.
Orin helps the clan against Nemuri but he's way too good for their men, they fall in great heaps on the ground. Orin leads Nemuri into further traps. The one in a temple is quite entertaining.
It's a black mass for Satan with a naked sacrifice. Nemuri slaughters many of the brethren. Nemuri is the son of a Chinese woman and a white missionary. He has a grudge against the missionaries and a general hatred for the rich and powerful.
There's plenty of action as Nemuri is attacked over and over again. He defeats the baddies and kills most of the clan. The boy leaves with Nemuri. Another entertaining entry in the series. Half way through the dozen films.