These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Rikuo: Like I said, your heart and your body... entrust everything to me!!
Complete Monster: Sanmoto Gorozaemon from Nurarihyon no Mago initially seems to be a member of Hagoromo Gitsune's entourage through his incarnation of Jizo, but in truth was using her in order to revive the Nue aka Abe no Seimei in order to get revenge on the Nura Clan. Formerly a human merchant in old Edo and suffering from boredom, he opted to dabble into the dark Hundred Tales' clan's power to unleash a swarm of Yokai that terrorized the nation through indiscriminate killing while Sanmoto brainwashed high ranking officials into his own personal cult. When cornered by the past hero Rihan Nura, Sanmoto opted to become a Yokai himself, resulting in even more death and destruction. In the future, Sanmoto secretly worked with the true Big Bad Abe no Seimei, transforming Rihan's first wife into an assassin to murder him in a child form, gloating over how she murdered the man she had loved while looking like the child the two could never have. Unlike most of the villains who either brainwashed or had aspirations of creating a paradise for yokai, Sanmoto was merely a vulgar man with a god complex who terrorized Edo for his own greedy ambitions. Even a side story delves into how vile he is: when he is rejected by a lady who disliked him, he responded by killing off her family and friends and then picked her up when she was destitute and mentally scarred from the ordeal.
For Foe Yay, Hagoromo (in current) form and Rikuo, not helped by the Battle Couple feel of the 2nd to last chapter of the series' cover
Fridge Brilliance: It doesn't seem to make sense that a yokai group would be so fervent about defending humans. But then: a large number of the major Nura clan characters used to be human. Kurotabou was created from a collection of children's stories about a protector of children. and the All Your Powers Combined special ability of Rikuo and Rihan requires the user to be part human. When it comes down on it, the Nura family needs a good mix of yokai and human blood to have the sort of power it did under Rihan.
Harsher in Hindsight: The 1st ending of the second season focused on oranges, which seems cute at first until you realize oranges were once a product of Sanmoto, the worst villain in the series, who once was an orange selling businessman
Jami and his Lord to the point that his Lord's wife was jealous.
Tall, dark, handsome, long-haired opponents Rihan and Kurotabou during the Edo period oh, ho so much.
Moral Event Horizon: Tamazuki crossed it when he killed his most loyal servant, Inugami for no reason other than to power up his sword.
The Nue crosses it in two ways, firstly casting his mother, who had been trying to reincarnate him for years, to hell; made all the more jarring since his Freudian Excuse involved her death in the first place, and secondly using Otome with Sanmoto's assistance in an assassination ploy in order to kill Rihan, especially since his need to be reborn led to the curse by his mother onto the Nura Clan which caused Otome to be infertile and thus opt for death, which led to her becoming the host of Hagoromo Gitsune in the first place.
Sanmoto for the above reasons, but his enjoyment through Jizo on how he emotionally manipulated Otome into murdering her lover and then gloating about it makes him arguably worse than the former.
Squick: Nurarihyon's head is like that because he's so old (one of those senior citizen things), of course, this also serves to make him better resemble the classic depiction of Nurarihyon. But Rikuo's own head will probably become the same when he ages.
EVERYTHING about Hagoromo Gitsune : an immortal fox demon which possess women bodies to survive and eats human kidneys in order to give birth to ancient evil monster that is already fully aware and intelligent while in her womb.Nightmare Fuel personified? Sure looks like it.
Abe no Seimei, as an infant not yet born
Sanmoto Gorōzaemon. Just, Sanmoto. Even Minagoroshi Jizou has nothing on him - oh wait...