The two-book series Konyaku Haki kara Hajimaru Akuyaku Reijou no Kangoku Slow Life is a masterwork of reaction comedy. Just a constant stream of glorious absurdity centered on a particularly charismatic psychopath which I would love to see animated one day (as admittedly unlikely as that is). My one and only complaint is that it goes much too far overboard with the yandere character.
The third Grimgar novel picks up right from where the Anime adaptation left off. And while I certainly liked that, what worked in a visual format doesn’t do so hot as text alone.
The main problem here is the same as that plaguing the Youkoso Jitsuryoku Shijou Shugi no Kyoushitsu e novels; the protagonist’s cringey inner monologue. Both adaptations downplay/eliminate that aspect and end up far better for it, and so as with that series I have to recommended avoiding these novels at all costs if you happened to enjoy the Anime.