Tonari no Youkai-san is a Slice of Life with elements of mystery and heavy drama. The setting is a fantasy world where "yokai" (imaginary beings brought to life due to power of rumors, emotions, desires etc..) live with humans.
Plot
The show starts when a 20 year old pet cat is reborn as a nekomata (a yokai cat with two tails and power to transform). As a newborn yokai, he starts learning the ways of this world and this allows us audience to tag along for the lessons. We keep meeting new characters (around 15+ major cast members at this point) which all have their own stories/backgrounds (both current and some flashbacks). At the same time, there is a larger mystery plot unraveling in the background. The pacing is great, leading to a decent climax that provides enough closure for this season.
Review
I definitely love the setting of humans and yokai living together in a slow slice of life with a rural backdrop. And the mystery behind the world's lore is also intriguing. And there are some ridiculous characters (eg: wagen-san) which are memorable.
But, the series has a few negatives:
1. The background stories of characters are often boring and predictable. And they say lines like "How could you understand how I feel?"..
2. Unnecessary "power of friendship" moments. Some dialogues like "I want to protect/save you" feel cringe when its middle schoolers (or even younger children) saying them.
3. Some drama is stretched too much and takes you out of the story.
I would recommend just watching the first episode. The series maintains the same vibe throughout the entire season and you can easily judge if it is to your taste. While I don't regret watching it, I don't exactly feel glad either. Its a decent enough series, that is worth its runtime, but nothing memorable.