The school attack is a post-credits scene in Attack on Titan: The Last Attack
Official X (formerly known as Twitter) account of Attack Titan anime teases one screenshot belong to Attack on caste in schoolsThat’s the post-credits scene Final attack. It shows Eren eating popcorn while sitting between geeky Armin and goth girl Mikasa.
Attack on caste in schools appears in episodes 21 to 34, depicting a modern version of the Attack Titan figure. Everyone lives in a normal high school and it’s a slice-of-life comedy, as opposed to the main story which is much darker. Despite the fact that this is essentially a standard modern AU, there are still quite a few similarities to the main series’ quirks and storylines. The film’s post-credits scene will use the final chapter of Episode 34.
Attack on Titan: Final Strike is one composite film of parts 3 and 4 of Attack on Titan: Final Season. In an interview with Crunchyroll, series director Yuichiro Hayashi speak that this was actually the optimal format to watch the series finale due to the way he originally storyboarded it Final chapters special. The film opens in Japan on November 8, 2024.
You can watch Attack Titan anime on streaming services like Crunchyroll.