J-rock with full fantasy-war grandeur, 藍井エイル’s “絵空事 (Esoragoto)” storms in as a cinematic rock opener built to carry kingdoms, armies, and Rimuru-level destiny. The title 絵空事 translates most naturally as “make-believe,” “fabrication,” or “beautiful fiction,” a poetic phrase for something imagined rather than real—perfect for a fantasy world where dreams literally reshape nations. Aoi Eir herself describes it as an intense rock number built around band sound and the epic scale of the series, which makes it one of her strongest modern anison power pieces.
The anime hook is massive: this is the official opening theme for TV animeThat Time I Got Reincarnated as a Slime Season 4 (転生したらスライムだった件 第4期), giving it instant crossover heat with both rock fans and the wider fantasy anime audience. Even better for your release-watch readers, the song is confirmed for CD release on April 22, 2026, and it arrives as part of a double tie-up single alongside “MONSTER,” the opening theme for Classroom of the Elite Season 4 Year 2 Arc, so there is a major single package orbiting this release
