Vampires suck blood because of the myths and legends right?
Dullahans are the harbingers of death because of myths and legends right?
Snow Women put curses on you because of myths and legends right?
Succubus' seduce because they can because of myths and legends right?
Demi-chan wa Kataritai sees these monsters in a more different light making the actual notion of having interview with monster girls a unique and comedic watch.
If this anime is anything to go by title, the anime is essentially talking and more talking, nothing more, the unique "flavour" to all this talking comes from are looking at the different light of "common" monsters,
be it playing against the type or using the monsters mythology and using it in a clever way at looking at monsters (be it through science or common sense on the part of monsters' behaviour) to it's advantage through usual comedic stances. Due to this, the characters are developed heavily, especially Yuki Kusakabe voiced by Shiina Natsukawa the snow woman and a little later on Sakie Satou voiced by Yoko Hikasa the succubus but the other main cast like Hikari Takanashi voiced by Kaede Hondo the vampire, Kyouko Machi voiced by Minami Shinoda the dullahan, Himari Takanashi voiced by Lynn, Hikari's twin sister and the main protagonist Tetsuo Takahashi voiced by Junichi Suwabe get a bit of disguised development through many of the banters the characters with each other (not just with Tetsuo mind you).
So going by characters, LA will just say it immediately but LA's favourite character went to Sakie Satou and no it's not because of her being a succubus (but still her natural beauty is a great bonus nonetheless *cough*), but she along with Hikari getting the best comedic skits in the anime for LA. Sakie's comedy revolves around her aphrodisiac effects on Tetsuo and BOTH of their overexaggrated expressions are comedic good albeit a running gag and outside of Tetsuo, she DOES talk about Tetsuo or her succubus effects to the other main casts with very hilarious moments. Hikari is probably the most dynamic of the main cast as she not only is the genkiest character of the series, but she like Sakie and Tetsuo interacts with the rest of the cast and she even gets serious and heartfelt especially during Yuki's opening arc. On speaking of Yuki, she is probably the next best character, as her being a snow woman, yes she is awfully shy at first but once she opens up and finishes her opening arc, she gains a very great personality and even better chemistry with the rest of the cast afterwords (with usually her running gag of laughing or trying to keep in her laughter from stupid puns). Kyouko Machi the dullahan has some stellar visually comedic moments (you can tell from the possibilities of being dullahan) also with her "being a dullahan and her many features" to her behaviour also makes light, again like the rest of the cast, she has great character chemistry. Next is Himari, Hikari's human twin sister, the stern yet loving sister to Hikari as well as having a rather tsundere relationship with Tetsuo, ashing out on him whenever Hikari tricks Himari into thinking Tetsuo has done something lewd to her and really her relationship with Hikari is a focal point in the anime in HAVING a "monster girl" as a family member, with hijinks ensuing at the same time prior thanks to Hikari. Finally we get to Tetsuo who is essentially both the catalyst and the reactant to most of the anime as a whole and he too has great character chemistry, from his awkward talks with Hikari and Kyouko to fun experiments with Yuki to his talks with Sakie about her being a succubus and her fanserviced effects on Tetsuo. LA will remind you that Tetsuo relationships with Hikari, Yuki and Kyouko are taken is a sorta harem way, HOWEVER he is still a genuine teacher to them and cares for them just not in the harem sense, Sakie is the only exception as she's a teacher just like Tetsuo is thus kinda makes sense they are pushing THAT more than Kyouko or Hikari, also to that point LA wouldn't mind Tetsuo and Sakie getting together, it's the most LOGICAL out of the bunch in LA's eyes. Aside from Tetsuo's character chemistry, he does get a bit of character development later on, mainly about his overreaching help towards the demi's and his dilemma if his help is isolating the demi instead of familiarizing the demis with humans more other than himself. What can LA say but the character cast are very dynamic and LA said this countless times, but the cast has great chemistry with one another and is probably the main reason to watch this anime.
In terms of animation done by A1-Pictures and the animation is actually pretty polished and very detailed to say the least, from the bright and poppy character designs to the beautiful backgrounds and even with it's comedic moments, sure it uses chibi faces at times but those faces are still in place of the detailed character designs at the same time and it can still be used to great effect due to the comedic timing, thus the animation is actually a great standout...nice job A1-Pictures.
With the great characters, the voice cast in it's entirety is amazing, what else can LA say, it felt like the voice cast knew the characters rather than the other way around. LA's favourite character goes to...pointing out the obvious...Yoko Hikasa. But still some standouts are Kaede Hondo as Hikari, Minami Shinoda as Kyouko, Shiina Natsukawa as Yuki and Junichi Suwabe as Tetsuo so yeah...the entire main cast.
Now, LA kinda needs to point out the elephant in the room, that being Demi-chan wa Kataritai's relationship with it's more *ahem* suave older brother anime Monster Musume no Iru Nichijou and LA will say the obvious but the fanservice compared to Monster Musume no Iru Nichijou is a bit more mature and slightly used for comedic effect (see Sakie for the obvious), saying the god damn obvious, but if you wanted see a less fanservice hell anime vers. of Monster Musume no Iru Nichjou, then this is an obvious pick, especially wanting to know a bit more of the world of Monster Musume no Iru Nichijou. LA will note that Demi-chan wa Kataritai still HAS fanservice and isn't just omitted and limited to Sakie, there's sprinkles of fanservice here and there but not to the point of what Monster Musume no Iri Nichijou takes it to.
If there were any flaws LA would list out (as much as LA is praising this anime), LA would just point out that if you think that Hikari is too hyper genki and on speaking of which, Hikari herself "flirts" with Tetsuo though it's taken for comedy so take that like you will, LA just more or less rolled LA's eyes at that notion but knew it was SUPPOSE to taken for comedy and was only used ONCE, anyways Hikari might get slightly annoying nonetheless. The most obvious flaw (which LA needs to point this flaw out, it's rather an opinion than a solid flaw) is that it's just an anime about comedic talking, nothing more and that can deter some of the audience.
Demi-chan wa Kataritai is a slight surprise of Winter 2017 for LA, merely due to how a simple premise can do so much with it and even get serious about certain matters (supernatural racism, "just being yourself" and pre-conceived notions can hurt) and the best strength LA has been constantly praising is of it's characters and their chemistry with one another. If you want to see a good punchline comedy anime with a more "heart" to it and greatly developed cast, then Demi-chan wa Kataritai is one to watch.