Is Kotoko a fair Goddess of Wisdom, or has the title warped her morality to the point she's a Tautological Templar with Blue-and-Orange Morality, especially given the events of the Sleeping Murder incident. Rikka certainly thinks is the latter, and wishes for Kurou to see Kotoko in that light as well.
Is Rikka justified on her actions given the abuse she received as a child? Did she decide she needed to do certain things, no matter the cost, in order to see her wish granted of becoming a regular human; or was the darkness present before that, and her goal and circumstances only happened to align with the need to release those dark impulses? Kurou believes Rikka might have had a darkness within her before the events that made them what they are, but he was also too infatuated with her as a young boy to be sure.
An Aesop: Two of them from the Steel Lady Nanase arc, maybe unintended but still pretty clear. It's better not to spread misinformation, lies and malicious rumours on the internet because they can easily grow beyond anyone's control and cause pain to everyone regardless of what was the original poster's intent. Also, don't believe everything you read on the internet as a fact.
Arc Fatigue: A common complaint with the anime is the amount of exposition and conjecture that can stretch out an episode. The Steel Lady Nanase arc in the first season starts in the second half of episode 3 and lasts all the way to the 12th and final episode of the first season, and the manga has a similar problem since the Steel Lady Nanase arc starts in the middle of the first volume and lasts till the very last chapter of volume 6. This is somewhat understandable when you consider that the first novel was all about Steel Lady Nanase.
A few brief scenes showing Kotoko interacting with the yokai come off as this, such as the beginning of Episode 2 when a ghostly cloth creature comes out from under Kotoko's skirt, or Kotoko being carried by a gigantic gashadokuro in the middle of the city.
The opening of Karin Nanase's show being showed in its entirety, as if it were the opening of another anime randomly pasted in the middle of an episode.
Complete Monster: The former head of the Sakurawaga family was a greedy man obsessed with the Kudans' power. Believing the Kudans' power to read the future would bring him fortune, Sakurawaga had Kudans hunted down and their meat fed to his family to test it, killing them. After numerous failed attempts, Sakurawaga came up with an idea to mix mermaid flesh with the Kudan meat, killing more and continuing until the end of his life. Even after death, his obsessions continue to haunt his family as he entrusted his mission to his descendants, reaching the modern day, causing Kuruo's Dark and Troubled Past and Rikka's descent to evil.
Designated Hero: Any readers/viewers wouldn't be wrong if they think that Kotoko is so blunt with self-righteousness when she tries to solve a case. But it helps that she's the Goddess the supernatural defers to and she's the only one (alongside Kuro) who can take on hostile monsters.
Fanfic Fuel: The cases Kotoko took for the supernatural community after she was deemed as the Goddess of Wisdom.
Fan Nickname: Among fans of both this series and Azur Lane, Kotoko is nicknamed "Crippled Niimi" due to her resemblance to z23, one of the starter units.
Growing the Beard: One of the biggest complaints about the early series is the amount of Arc Fatigue that occurs due to the Steel Lady Nanase lasting to volume 6/end of the first season of the anime. Volume 7 onwards has been better received due to more emphasis on shorter, more self-contained cases.
Magnificent Bitch: The protagonist Kotoko Iwanaga is revered as a Goddess of Wisdom by the youkai and keeper of order. Taking drastic measures to maintain order, Kotoko uses her intelligence and people reading skills to weave lies to satisfy her clients' wishes, using force and even framing a dead woman to stop a rampaging phantom. She also shows no mercy to those who try to interfere with order, punishing those who tamper with it through her truths and lies, unconcerned of the consequences for those around. Intelligent and ruthless, Kotoko's sharp wit and charisma shows why many worship her as a deity of knowledge.
Memetic Mutation: The photo of Kotoko about to be punched by Saki made the rounds with people who read the manga/novel or watched the anime.
It Was His Sled: It's hard to talk about the series without quickly bumping into the spoiler that Rikka is actually not only still alive, but also the Big Bad.
Ship-to-Ship Combat: Expect an In/Spectre debate/topic to include Kuro and being paired with either Kotoko or Saki. Some suggest Rikka, but as an extreme option.
They Wasted a Perfectly Good Plot: Some backstory regarding the previous Goddess of Wisdom would have been good backstory material and what made the supernatural pick Kotoko in the first place.
The Woobie: Saki comes across as this. She went to university yet became a lowly traffic cop, she broke up with her boyfriend Kuro after discovering the existence of the supernatural (which left her with serious mental scars), and she's forced to help his new girlfriend Kotoko who also deals with the supernatural and yokai (Saki is scared of them). Kotoko's plans require spreading a rumor online that she (Saki) is a possible prime suspect in Detective Terada's murder, and Saki is also forced to watch her former boyfriend being messily murdered by Steel Lady Nanase over and over again, since it's the only way for him to activate his precognitive powers. In the end she's also forced to admit that Kotoko and Kuro are a couple now and that she will never see him anymore.
by Mamoru Miyano, which gives a jazzy feeling.