WARNING: The following contains spoilers for Episode 5 of The Slime Diaries, "Return of the Summer Festival" now streaming on Crunchyroll.
Like many isekai anime, The Slime Diaries features certain tropes characteristic of the genre and anime as a whole. Episode 5, "Return of the Summer Festival," does just that, focusing on a very popular anime trope often used in slice-of-life or romance anime. In real-world Japan, the summer festival generally focuses on a specific shrine and focuses the celebration around it. In anime, it's more of an end-of-summer celebration, enjoying the harvest, the weather, and one's community.
Rimuru, once from a normal version of Earth, misses these summer festivals and suggests to his council that they should have one -- in a week. His council members take up the call with glee, eager to please Rimuru and to have themselves a party. Throughout the week they set up food and game stalls, as well as places to showcase the local artistic talent. Rimuru sees all of this and grows increasingly excited.
Episode 5 directly addresses why this classic anime trope is so important. As the spin-off of That Time I Got Reincarnated as a Slime, The Slime Diaries focuses on the small, daily events that make up the characters' lives, and it shows precisely how much the summer festival means to the citizens of Tempest. It's a reason to come together and share their talents, be it cooking, crafting or performing.
They even go so far as to try and mimic one of Rimuru's favorite treats from his own world: takoyaki. Unfortunately, Tempest does not have octopuses native to the area, but they improvise with a similar creature, though they don't want Rimuru to see that. Their efforts are worth it, as Rimuru is incredibly happy to fulfill the nostalgia of an old favorite. He loves the takoyaki and praises their efforts in trying to replicate a foreign food.
Tempest's summer festival also features a parade but with only one float -- a giant slime that is obviously meant to be Rimuru. On the top, he stands, unsure how to process the moment. He feels bad that citizens are pulling this heavy float, but Shion assures him that it brings them happiness to celebrate their leader and show their loyalty.
The festival ends with a dance and a fireworks performance, with the grand finale being a giant firework that explodes in the shape of Rimuru. Throughout these scenes, Rimuru is extraordinarily happy and remarks on the feeling. He mentions how this feeling is exactly the purpose of these festivals -- to bring the community together as one and to experience fun. The episode doesn't focus on any particular character, rather showing how ecstatic they all become in the process and fruition of the summer festival.
The Slime Diaries does a great job using a classic anime trope to show characters enjoying life in the moment, with no thought of the future or the past. The trope is used to the best of its ability and specifically shows why it's a trope in the first place. It can be a pivotal moment in an anime when a community can either come together or potentially begin to fall apart. The Slime Diaries shows the best sides of the summer festival, making Episode 5 a very happy and satisfying experience.