Americans Hate Tingle: There was a time in which the manga was being promoted left and right in Spain, which caused many people to become tired of the series even before reading it. Ironically, and probably as a consequence of this, the anime wasn't even licensed there, despite being exactly the kind of product which distribution company Selecta Visión (which had and still has the monopoly of anime in Spain) would have bought only to make a fast buck.
Benio often being subject to The Worf Effect. Although even Rokuro doubted he could win against her it still doesn't sit well with many fans who wanted them to be more equal. To them Benio is nearly a Damsel Scrappy, who rushes in, gets her ass kicked, then needs Rokuro or even Mayura to save her. Others will point out that Rokuro doesn't do much better, and that in fights, like those against Kamui and Yuuto, both Benio and Rokuro did about equal work.
In relation to the above, Mayura has caused some of this, as some fans consider she stole Benio's spotlight even though she should be much weaker.
The anime also caused a lot of conflict between anime-only watchers and those who had read the manga. Most of the latter group feel that the anime's Adaptation Decay went too far, especially concerning Rokuro's characterization and the (seen as pointless) addition of Kinako.
Big-Lipped Alligator Moment: The anime has a few. Depending on how tolerant you are, from a couple to a dozen at least. Most notable are the basara Suzu's (anime-only) dance and song sequences: the first time she did it in her introduction was bad enough, but then she came back and draggedBenio and Rokuro into it...
Cliché Storm: One of the most common criticisms. For some, it's hard to get excited about the series when almost everything about it has been done before in both Shōnen Genre manga and Onmyodo-themed works (the latter being bad enough that the manga's very title is one of its many references to those). Part of the problem is that, while there are some subverted tropes and unexpected plot twists (to cite only two, who saw Benio losing her powers coming? Or even Mayura getting so much character development instead of being a token Clingy Jealous Girl of a Childhood Friend?), they tend to be in the later parts of the manga. Even then, chapter 38 in particular got hit pretty hard when the readers realized that the story was about to go into the usual shonen-style Tournament Arc.
Complete Monster: In the anime, Yūto Ijika corrupted innocent students into mindless, violent Impurities, forcing Rokuro to kill them. Traumatizing Rokuro to make him abandon exorcism, Yūto later mocks him for the horror he put him through. When his sister, Benio, finds out the truth of his vile deeds, Yūto mocks her, revealing he never cared about her. After corrupting Rokuro's childhood friend into another impurity, Yūto later wounds Benio and smashes her precious hairpin he gave her. Recovering from his injuries, Yūto torments Rokuro and Benio, and after being defeated in the final battle, he threatens to launch an attack on the human world. Mortally wounded, Yūto "congratulates" Rokuro for becoming a being prophesized to destroy the world.
Not many people were really that impressed with this series early on since it came off like it was going to turn out to be yet another addition to the long and cliche Harem Genre list. However, it eventually developed its own voice due to establishing Rokuro and Benio as the Official Couple right away, and the Hopeless Suitor, Mayura, got to move on to possibly developing a relationship with Shimon.
It also notably shifted in intent after the first Time Skip, as while the large Cliché Storm never quite goes away, the world-building, political complications of the protagonists and the growth and actions of those around them starts expanding outwards to a growing cast of noteworthy characters. It's not a stretch to say that the whole first eighteen chapters (at five volumes) are little more than a prologue to the larger story.
Les Yay: Benio was pretty popular at her old school. She also has quite a bit of chemistry with Mayura, in the sixth episode of the anime especially.
Memetic Mutation: This reaction shot◊ of Mayura in Episode 34 is well on its way to becoming this for the sudden, out-of-nowhere Art Shift resulting in equal parts creepy and hilarious.
Moral Event Horizon: Yuuto caused the death of a entire dorm of kids, and only got worse from there.
Narm: In the anime, the sheer amount of times Rokuro screams due to rage or sadness is this, due to the fact that it happens so often. Not helping matters is that his face becomes distorted, to the point it becomes weird and loses dramatic effect. Natsuki Hanae, despite his talent, can only pull off that many screams before it becomes grating.
Padding: The anime adaptation suffers greatly from this. It took 20 episodes to reach the end of the fight against Yuuto, but to get there, material from the manga was greatly extended with many filler scenes throughout said 20 episodes. After that, the anime goes into complete anime-original territory.
Rescued from the Scrappy Heap: Having finally been properly introduced to the manga at the end of chapter 36, the familiar, Kinako, who's greatly hated for being a pointless addition to the anime series, has had a better reception so far trying to protect the Adashino house on the island. It helps that soon after his introduction, Rokuro takes the Adashino house for his own to save it, leading to a far less antagonistic relationship between the two.
Benio's formerly anime exclusive familiar, Kinako, is this to several fans, who see him as annoying and a pointless addition to the series.
Yuuto, at least in the anime, isn't very well liked for being a cliched and, so far, depthless antagonist. He comes off more as the plot device of Rokuro's angst rather than a character in his own right. The fact that there was no flashback of his time in Hinatsuki in the anime certainly doesn't help.
It takes a while to some fans to realize Kamui is male, although he is always shown bare chested, mainly because of his long eyelashes.
Funnily enough, it happened again with Hijirimaru. A translator even commented on being confused over his use of "ore". Probably because twin tails are a traditionally female hairstyle.
This is no longer Basara-exclusive with the arrival of Tenma. His anime design is even worst, as he has much longer hair.
◊ of Mayura in Episode 34 is well on its way to becoming this for the sudden, out-of-nowhere Art Shift resulting in equal parts creepy and hilarious.
