- Awesome Music: "Crawl" and "Aru ga Mama" (the anime's opening and second ending song, respectively). "Yureru Kokoro" from the OST also qualifies; it's simultaneously strong and mournful and enhances the emotional impact of several scenes.
- Complete Monster: Miharu's seemingly-aloof ally, Fuuma Kotarou, is the true mastermind behind the tragedy surrounding the former's life. A 117-year-old ninja with shapeshifting powers, he manipulates multiple important people to obtain the Shinrabanshou so he can become God. Posing as Inasa, he founds Kasa and uses the organization to train children and teenagers into becoming his expendable assassins. A decade before the story, he brutally killed a four-year-old Miharu in front of his mother, hoping to drive the latter to despair. In the story's climax, he betrays and murders his partner, before trying to steal the Shinranbanshou from Miharu—knowing doing so would kill Miharu—and tortures Tobari while he orders his servants to kill all of Miharu's friends.
- Ensemble Dark Horse: Judging by YouTube comments, Gau is quite popular in the English-speaking fandom.
- Fanon: The fans seem to like making Raimei a Yaoi Fangirl, or at least a Shipper on Deck for Miharu and Yoite.
- Fan-Preferred Couple: Miharu/Yoite, Raikou/Gau, and Kouichi/Raimei.
- Fashion-Victim Villain: Raikou for sure, except for the outright "villain" part. His work clothes include something like a denim vest, a hakama over jeans, and sandals. His casual clothes are canonically recognized as really, really, really terrible. He has seriously considered buying a coat of gold sequins. And one with giant stars across it. And has worn a shirt with huge feathers hanging off the back.
- Foe Yay: Miharu and Yoite start out like this, but are really, really bad at acting like foes, and it quickly blossoms into full-fledged Ho Yay, especially after Miharu's Hazy Feel Turn. There's some minor Foe Yay between Kumohira and Yukimi too. Not to mention the rather creepy scene where Hattori is practically hitting on Yoite - "You really are diligent and smart... as well as beautiful."
- Het Is Ew: Some fans were freaked at the possibility that Yoite could be a girl. He's actually intersex.
- Subverted with Kouichi/Raimei being one of the general fan preferred pairings.
- Informed Wrongness: Much is made of how immoral Oda Yae's Mind Reading technique is. While she does use it in unsavory ways, Tobari's declaration that using it makes her worse than Nowake (who, depending on the medium, either killed Yae's daughter or allowed said character to die), is a little hard to swallow, especially since the person she was using it on at the time was an enemy.
- Iron Woobie: Raimei has been through a lot of crap, between losing her entire family except her brother (who killed them), losing her brother too (anime only) and losing her boyfriend (manga only). But she never backs down.
- Just Here For The Ho Yay: See LGBT fanbase, below.
- LGBT Fanbase: Somewhat unsurprisingly, the series has a sizable LGBT fanbase.
- Memetic Molester: Hattori may have risen to this, thanks to all the neck-touching. And his 'praise' of Yoite.
- Memetic Mutation: Gay - I mean, Gau!
- Moral Event Horizon: Fuuma killing four-year-old Miharu.
- Raikou nearly crosses it when he tries to kill Raimei, only to be stopped by Gau.
- Narm: In the last episode of the anime, a smiling image of the dead Raikou appears in the sky as Raimei and Gau are talking about him. Given how old and frequently parodied that device is, it's hard to take it seriously.
- Nightmare Fuel: Among other things, 4-year-old Miharu getting his face blown off and Asahi's body falling to pieces.
- Stoic Woobie: Miharu and Yoite.
YMMV / Nabari no Ou