- Awesome Music: Say what you will about the series, but the opening theme and accompanying animation are superb.
- Broken Base: The anime is not very popular with fans of the original novel series, as several of the more complex interactions and dialogue were cut or altered. The end result is just another generic dark fantasy anime with absolutely zero context whatsoever. Due to this compression, the adaptation begins to suffer Seasonal Rot as soon as episodes 3 or 4. The absence of romantic subplots is also a point of debate for the series.
- Base-Breaking Character:
- Is the Mercenary a rather original protagonist with a defined backstory and goals? Or was he made a bastardized caricature of tropes related to dark fantasy? Or worse, is he a disgraceful interpretation of the original character?
- Furries really want Mercenary to be the true protagonist. They don't give a damn about the rest of the cast.
- Best Known for the Fanservice: Mercenary was a very different take on light novel protagonists at the time. And that's all people know the anime for nowadays. He got prevalence in most advertising and promos for the series over Zero.
- Memetic Mutation: Because of the strong similarity of the full Japanese name with the original name Re:Zero and the animation studio, a lot of jokes were devoted to how some people mistook this anime for its second season or a spin-off.
- Fan-Preferred Couple: Grimoire of Zero is known for its Crack Pairing, since despite the absence of a romance in series and obvious problems of pairing between a miniature girl and a large mighty man, many fans of this work hope to see in the future any hint of feelings development between Zero and the Mercenary.
- Popular with Furries: Invoked with Mercenary and his Mr. Fanservice status. The promos seem to be aimed specifically at furries.
- It Was His Sled: Because of how ridiculous it looks, it's too easy to figure out early on that Albus is actually a girl.
- Hilarious in Hindsight:
- Just like Re Zero, Grimoire of Zero features a white-haired wizard as the main female character who is much older than she seems and has odd interpretations of morality. And of course, Takehito Koyasu plays the Obviously Evil Anti-Hero who changes sides. It happens when both series are animated by White Fox.
- Albus's outfit gave people the wrong idea. Since it resembles a track suit, viewers believed they were a traveler from another world.
- Karma Houdini: Holdem and Thirteenth get off fairly easily for their actions. Their punishment basically amounts to scowling and a "well, now he's on our side!" reaction.
- The Scrappy: Even when their identity is concealed, Albus causes much more trouble than he's worth- and that's exactly why everyone loathes him. In episode 2, he approaches the village elder with a missing ring on his finger. Instead of doing the reasonable thing and taking it off to return it to the woman, he does the bad thing and keeps it on.
- Special Effect Failure: The CG crowds from the last few episodes look very fake and just... weird. The main characters, who are animated normally, stand out too much from the CG, making it look weird.
- Squick: Mercenary is not pleased in the least with his new reputation as a lecherous degenerate when Zero and Albus claim that they are his sex slaves so they can pass into a town without investing lots of money.
- What an Idiot!: Starting a civil war among witches, triggering a justified Witch Hunt, is not the right way to create a tolerant world that appreciates magic, you idiots!
- What Do You Mean, It's for Kids?: What starts as a fairly harmless dark fantasy anime aimed at younger audiences turns into a colossal Shocking Swerve featuring sex slaves, interspecies romance and genocide. And then there's the pedophilia jokes. Of course it was gonna raise a few eyebrows.
YMMV / Grimoire Of Zero