- Awesome Music: "No Mercy
" from the first OVA.- And "JESUS JESUS" from the second OVA.
- And "JESUS JESUS
- Big-Lipped Alligator Moment: Any of the moments where Aneyama shows something that can be described as making him remotely sympathetic, due to him immediately committing some horrible act of violence towards the other character in the scene because of an incredibly minor infraction against him. The author probably intended for these to be a Bait the Dog moment, but they come across as being so unnecessary to the plot aside from establishing how much of a monster Aneyama is that they come across as completely nonsensical.
- Complete Monster: Mizuguchi Kikuya, from Volumes 6 and 7, is the cannibalistic, sociopathic Yakuza leader of the Mizuguchi Gang, and a servant of Mukai. Originally tasked by Mukai with discovering the origins of Saiga Riki-Oh in exchange for power, Mizuguchi murdered Riki's adoptive father and drove his family into bankruptcy. Under Hina's orders, Mizuguchi gathered over 10,000 of the homeless following the earthquakes and fed them all poison, ordering his own men to burn the corpses and any possible survivors regardless of age. Holding Iwato's young daughter hostage for his servitude, he manipulates her into loving him, hoping to rape her when she turns 15. Capturing Riki and planning to eat him, after Mizuguchi is tortured by Aneyama and promises to kill Riki, Mizuguchi taunts Riki with the deaths of his friends and family, hoping to overtake Aneyama as Mukai's new second-in-command and gain even more power.
- Crazy Is Cool: If you thought the movie was weird, based off the first story arc, you ain't seen nothing! Cyborgs, men who hide knives in their skin, hypnotic wolf-themed villain, cannibals, and more weird stuff! Riki is one big crazy awesome himself.
- Crosses the Line Twice: While tending to his roses, Washizaki casually mentions an ongoing project of his to destroy the ozone layer.
Otto: By 1999, the likelihood of developing skin cancer from exposure to ultraviolet rays should increase tenfold.
- Ending Fatigue: The battle against Mukai is easily the least popular part of the story among Riki-Oh fans, due to how Unintentionally Unsympathetic Mukai is due to his actions List of things that Mukai has done He also comes across as being less interesting than the previous antagonists, who all had some sort of gimmick to them, while Mukai is simply a Raoh Expy.
- Fan Nickname: Fist of the Jew Star, due to the protagonist's similarities to Kenshiro and the Star of David on his fist.
- Fridge Horror: Crosses over with Fridge Brilliance. The fact that Riki-Oh's nightmare vision of Mizuguchi has him imagine him as a horrifying monster even after he killed him shows that Mizuguchi actually managed to traumatize him so badly that he's unable to see him as human due to being so scared of him.
- Harsher in Hindsight: The Cape arc features a nuclear power plant failing to cool down the reactor. The situation is worsened by a tsunami.
- Hilarious in Hindsight:
- The Disciples of the Wolf Commandments are extremely similar in appearance and behavior to the Wolfpack Boss, the Shamans, from MadWorld, which would be released far after Riki-Oh.
- One of the two Yakuza harassing an elderly couple that Riki-Oh kills greatly resembles the Scout from Team Fortress 2.
- Moral Event Horizon: Yomi crosses it by skinning alive the young boy Riki befriended.
- Narm:
- Riki's catchphrase of "I'll send your karma to hell!!!" comes across as being incredibly unthreatening, both due to how bizarre it sounds, and also making it sound like Riki-Oh is after the karma of his opponents rather than the opponents themselves.
- Umibozou cartoonishly hopping around while holding his groin in pain after Riki-Oh knees it, mainly due to it being a very small panel which is thus drawn in a less detailed fashion, making it look like something out of a comedy manga.
- One of the Yakuza members claiming it's unusual how Riki-Oh's trying to kill Eisaku slowly due to him usually killing his enemies at high speeds to prevent them from suffering is this, due to him giving many a enemy of his a gory and horrific demise, as well as this statement not being true due to the Warden dying slowly from bleeding out at Riki-Oh's hands.
- The Baron can be hard to take seriously due to his tacky outfit and bizarre, crazed behavior making him seem less like an eccentric-to-the-point-of-insanity mad scientist and more like a kooky old man, as he does things like complain and call Riki-Oh gloomy when the latter calls him out for manipulating the dead, and then spooking him by turning his head 180 degrees and shouting "Boo!" before laughing about it and remarking that surprising people makes him feel truly happy and that he'll never stop being human even if he's dead because of that.
- Narm Charm:
- The entire thing, really. It's bizarre, nonsensical, juvenile, and filled with tasteless violence, yet due to the slick, detailed, and expressive artstyle, the many imaginative, bizarre, memorable, and larger-than-life characters, plus it's complete and utter sincerity, it manages to be an incredibly entertaining manga.
- Aneyama as a whole couunts as this as his cartoonish levels of villainy, due to him being a slave-owning, abuse-enabling, underling-killing madman whose also a literal Nazi that's prone to Big Lipped Alligator Moments one after the other with the bizarre contraptions he keeps around solely for killing minions who offend him in the slightest ways possible, and whose excuse for being gay is that he mourned his dead sister too much, doesn't do anything to make him any less of a disgusting, reprehensible, bastard.
- Nausea Fuel:
- The aforementioned tasteless violence can get REALLY disgusting and cringeworthy, as characters get skinned, have their limbs decapitated, and even holes punched through them. The semi-realistic art-style of Tetsuya Saruwatari and the sheer amount of detail it has doesn't help either, so squeamish and gore-sensitive manga fans might not want to read this manga.
- Nightmare Fuel:
- Washizaki's head bulging and puking maggots is the stuff of nightmares.
- In the same arc, there's a scene where Riki-Oh finds nuclear waste containers, what does he find inside? The irradiated decaying corpses of children.
- Shirt Stripping.
- There's plenty of flesh trauma. Nachi turns it into an artform by blowing the skin off numerous people including Washizaki.
- Momiji, the personal chef of Mizuguchi, whose fighting style consists of flaying his enemy alive with special kitchen knives, as well as his intention to turn Riki-Oh into a meal for Mizuguchi to eat, which is an inherently psychologically horrifying thought. Even the fact that he dresses up in a typical sushi chef's outfit arguably makes him even more horrifying, given that it comes across as him being so disconnected from human morality that killing and cooking people is just his job for him.
- They Wasted a Perfectly Good Character:
- Nachi, the brother of Riki-Oh. Given that he's displayed as having far greater powers than Riki, on top of being revealed to have been working with the antagonists, as well as one of Riki's biggest motivations is to try and redeem himself for selfishly abandoning him when they were both children, one would expect Riki to have a grand, climatic battle with him that would end with Nachi forgiving Riki and joining his side, but he winds up dying at the climax of the Cape arc, which isn't even halfway through the story.
- They Wasted a Perfectly Good Plot:
- Despite Nachi forgiving Riki for his selfish behavior in the past, he never joins forces with him and kicks ass by his side, although admittedly they would have been an extremely overpowered duo.
