世界輪廻

"Sekai Rinne" was released on 31 July 2024 as the opening theme of the television anime Naze Boku no Sekai o Dare mo Oboete Inai no ka?. It was the band's first release after moving to FABTONE and their first single written as an anime tie-in. Two editions were made: a standard CD (ANKM-0046, 1,430 yen including tax) and a deluxe set with a booklet (ANKM-0047, 2,200 yen). Both hold the same four tracks — the title song, the coupling "Ready for a new stage", and instrumental versions of both. There are two films. An official music video, and a short piece cut for television advertising around the anime's broadcast; both are on the band's own YouTube channel. The anime's production company put out a creditless version of the opening as well. Both songs went onto Gate of Heaven in November 2025, the title track at two and "Ready for a new stage" at seven. The pattern the band followed from here — singles first, album afterwards — starts with this record.