* CompleteMonster: Lord Naritsugu is TheCaligula to an insane degree. His very first scene has him raping the daughter-in-law of a lord who's hosting him for the night, and then killing her husband for good measure. This isn't an isolated incident, either. Naritsugu has been doing this for so long, he threatens the very stability of the nation, and nobody can touch him as he's the Shogun's brother. Later, we see him tie up a family for target practice ([[WouldHurtAChild including a little girl]]) and hear how he massacred a peasant revolt, taking the leader's daughter, after cutting out her tongue and chopping off her limbs, for his use as a sex slave. His only reaction to seeing the titular assassins mow down his loyal soldiers who die in defense of him is to contemplate how amazing the era of war must have been while deciding to return to such days.
* CrazyAwesome: Kiga.
* HolyShitQuotient: The 45 minute climax has this in '''spades'''.
* LoveToHate: Naritsugu. Big time.
* MoralEventHorizon: Nartisugu pole-vaults over it during his first appearance and keeps on plummeting further down with every second he spends on screen. Trying to actually list his misdeeds would result in a full summary of the film.
* NightmareFuel: Shinzaemon's reaction when he meets the "poor woman". But this also gives him the resolve to fulfill his mission.
* TooCoolToLive:[[spoiler: Subverted with Kiga and Shinzaemon's nephew, but played straight with just about everyone else in the group.]]
* ValuesDissonance: Japan doesn't have a problem with non-sexual nudity or children being naked. There's a long shot of a naked little boy, about 6, peeing in a ditch. This is a funny gag to Japanese Cinema (a similar joke would be picking your nose in the West) but it can be jarring to foreign audiences to whom "naked children" means "PedoHunt".