- Complete Monster:
- Akinari Kato is a tyrannical Daimyo who rules the lands of Aizu in a hedonistic hell where he has girls abducted to serve as slaves and toys for his pleasure before allowing his pet psycho squad, The Seven Spears, to torture them to death. When his vassal, Mondo Hori, rebels to save his daughter from such a fate, Akinari has him and the Hori men tortured to death. Throughout the series, Akinari abuses, tortures and rapes those who fall into his clutches, and when he is so terrified by Jubei Yagyu's constantly hounding him, he makes himself feel better by abducting and violating the innocent daughter of a lord who had the bad fortune to host him for a night. When he finally gets a hold of the surviving Hori women, Akinari sentences them to death by crucifixion and orders it to be made as drawn out as humanly possible.
- Dohaku Ashina, the ruler of the Ashina ninja and the secret ruler of Aizu who pulls Akinari's strings, soon reveals himself to be the true villain. Dohaku is a 107-year-old immortal man and when Jubei begins his heroic actions in Aizu, Dohaku's response is to begin having random women beheaded and their heads displayed as a deterrent. He then proceeds to have multiple women abducted for Akinari's harem or to be sacrificed in his dark rituals. Worse still, he raised his own beautiful young daughter as Akinari's concubine to get an heir from Akinaris bloodline, intending to do away with Akinari and Akinari's trueborn son. When Oyura ends up intercepting a blow Dohaku had meant for Jubei, Dohaku breaks down, screaming furiously how all she was to him was something to produce a Puppet King and refusing to save her life.
- Uroshido Koshichiro is the leader of the Seven Spears and Akinari's right-hand-man. A talented Master Swordsman who serves as an Evil Counterpart to Jubei with equal skill, but none of the honor, virtue or goodness, Koshichiro opens the series dragging the men of Hori before the Hori women and then promptly initiating a slaughter of the women just to hurt the men more. Koshichiro leads the Spears in their disposal of women Akinari is bored with and kidnaps newlywed couples to frame Jubei's ally Princess Sen as a rapist, forcing concubines to rape the men and giving the women to Akinari. While Koshichiro is seen as a Worthy Opponent by Jubei, Jubei makes it clear it is only because he deeply desires to face Koshichiro's skill against his own and makes it clear that he has nothing but hatred and contempt for the man himself.
- Funny Moments:
- When Otori and Oshina say they're jealous of Okei because Juubei's been really nice to her, he makes one of the most hilarious faces imaginable.
- Jubei and Takuan are trying to discuss their options for escape from Akinari's castle. The entire time, Oyura, under the influence of a powerful aphrodisiac, keeps crawling all over Jubei and begging him to have sex with her, while he just frowns in exasperation and tries to fend her off. Takuan seems more amused by Jubei's plight than anything else.
- Magnificent Bastard: Jubei.
- Moral Event Horizon
- The Spears cross it when they break into the divorce temple to butcher the Hori women in front of the Hori men
- Akinari is a nasty bastard from the get go, but his rape of Otone is what seals the deal
- Dohaku's is either ordering innocent women killed as a message to Jubei, or his reaction to Oyura's death at his own hand.
- What Do You Mean, It's Not Symbolic?: Koshichiro tends to place a cherry blossom twig between his teeth before he starts killing. It's a symbol for death and life's fragility. The series never tells you this, though.
YMMV / The Yagyu Ninja Scrolls