The Slime Diaries feels like a reward. We’ve watched Rimuru tackle hardships and make new friends, resulting in the peaceful monster town of Tempest. When shows like Attack on Titan or Demon Slayer want to indulge in a slice-of-life spin-off, they tend to move the characters to a different setting (usually a high school). But Slime Diaries succeeds in fitting into the canon of That Time I Got Reincarnated as a Slime almost seamlessly.
Set in between Seasons 1 and 2, the spinoff focuses on the daily lives of the people of Tempest and Rimuru’s attempts to introduce them to his favorite parts of Japanese culture. This clash of cultures and the receptiveness of the townspeople leads to plenty of situations that are equal parts amusing and wholesome. This likely couldn’t have been achieved if not for the storytelling and comedic character writing of the main series. Nothing in Slime Diaries feels particularly out of place, because we’re already used to seeing how each of these characters interact with each other. Likewise, while comedy spinoffs can often turn characters into a parody of themselves, Slime Diaries is able to resist the urge.
Therefore, the main draw of Slime Diaries is simply the chance to spend some quality time with its characters: twelve episodes in which Rimuru doesn’t go on a big adventure, but instead stays home to spend roughly a year with his friends. This ends up being a bigger appeal than you’d expect. The main series is always moving forward, introducing new characters and new conflicts, but that means that we often don’t have the time to see how the new members of the town are settling in. We got the occasional check-in with Gabiru, and we saw Geld trying to redeem himself at the start of Season 2, but now we have plenty of opportunities to peek into their daily activities.
Cycling through each of the seasons can make events feel a little predictable, but it allows the show to change sceneries without having to change locations. In some ways, this can sometimes make Slime Diaries more visually appealing than the main series. Both the background art and the lighting effects achieve their goal in making Tempest feel like a place that’s worth spending time in. This is an essential component to any slice-of-life, and the artists clearly took this to heart. Rimuru regards the town and its people as precious, and after watching The Slime Diaries, so will you.
Both the spinoff and main series are created at Studio 8-Bit, but with different teams in charge. Although The Slime Diaries is directed by the graphic design lead and CG producer of the main show Yūji Haibara, the appeal of the 2D art remained a focus. With new character designs, the whole cast looks a little more fresh-faced, smoothing over the sharper details from their more action-focused adventures. The result is a show that still has plenty of well-animated moments, but in a different form. The appeal of Slime Diaries is therefore not explosions or awesome sword battles (although they have plenty of excellent examples), but moments such as a memorable Gabiru dance or an adorable goblin girl climbing upon the shoulders of a large orc. The character animation acts as both a draw and an essential storytelling device.
Rimuru himself ends up being a new type of icon within this iteration. He’s a different kind of protagonist than we’re used to from isekai anime with a cute character design and a wholesome outlook, and that’s only been expanded upon. We’ve seen hints at his ambiguous gender expression after his melding with Shizu in the first season of the main series, but Slime Diaries indulges in having him don plenty of seasonal outfits. While the main series tries to focus on the fantasy aspects of the premise, Slime Diaries can be somewhat of a fashion show at times, with some members of the cast appearing in both modern and traditional outfits. Much like the background artists, it’s another way of demonstrating that this is a living, breathing world.
Slime Diaries is not only wholesome, but also genuinely funny. Of course, comedy is always going to be subjective, but here it’s reliable in the sense that it mostly expands on the comedy from the main show. It helps that the manga was written by Fuse, giving a sense of consistency to the character writing. No matter the gag, nothing the characters do will change your perception of them. Milim is still rash and immature, but now we get to see more of how that would manifest in normal, day-to-day life. Souei is still serious and brooding, but how long can he really keep that up? He’s got to unwind sometimes.
The Slime Diaries adds to the experience of watching That Time I Got Reincarnated as a Slime. Of course, you can skip it without really missing anything plot-relevant, but it helps to increase the dramatic weight of the events in Season 2. More cynically, I imagine it would also encourage more people to purchase Slime merchandise and roll for their favorite characters in the Lord of Tempest gacha game, but it’s a welcome addition nonetheless. Slime is already becoming an increasingly popular franchise, and if the anime were to continue, then so should The Slime Diaries. If nothing else, it is a way of giving us a wholesome check-in on all the new townspeople as the story advances. I imagine we’ll be needing it.