Spiral

Origin and reception

The opening theme for Mushoku Tensei’s second season, titled "Spiral," debuted in May 2023. It quickly gained traction, amassing over 4.5 million streams according to Real Sound. The band Longman later included the track on their second full-length album "10/4," released on October 4, 2023, featuring it on the album’s jacket and tracklist. The first limited edition of the album comes with a DVD containing music videos for the album’s songs plus a behind-the-scenes making-of video. By September 29, 2023, the song had been streamed 5.51 million times on Spotify.

Animehunch analyzed the opening sequence as a visual story told from Rudeus’s point of view, highlighting his desire to reunite with his loved one. This longing is shown through the gentle intertwining of hands, while the other figure remains blank, representing his still-unfinished search. The sequence also revisits Rudeus’s past adventures as he moves forward, followed by a transformative moment where he climbs a spiral staircase. This staircase acts as a metaphor for his personal growth and his active role in shaping his own fate. Overall, the opening captures Rudeus’s deep yearning, his evolution, and the adventure ahead.

"Spiral" won the "Favorite Opening Theme Song" award in the Summer 2023 Anime Awards from Anime Trending. In an AnimeAnime survey asking which summer 2023 anime opening theme song people liked, it placed seventh overall and third among male voters. It ranked fourth in Anime Corner’s theme song ranking. Daiichi Kosho Co., Ltd. also conducted a karaoke ranking survey for TV anime theme songs from summer 2023 works on the online karaoke service DAM, where "Spiral" took third place.

Production

Hiroya Hirai, the composer behind the song, crafted it with a specific scene in mind: the climax of the first season’s twenty-third episode, where Rudeus Greyrat gets to his feet and leaves after Eris abandons him. The track was designed to fit seamlessly into that moment. Hirai drew inspiration from Yuiko Ōhara’s earlier work on the season’s themes. Once the song was finished, Ōhara herself called the band, taken aback by what they had created.

Initially, Hirai planned to submit just two songs, but he ended up writing six. He polished three of those, narrowed the field to two, and ultimately chose “Spiral.” The process happened while he was on tour with a packed schedule, yet he found it exhilarating. The band was so productive that even the five rejected tracks felt strong enough to warrant a future release in some other form.

Lyrically, Hirai aimed to speak beyond Rudeus’s personal story, wanting to connect with hikikomori in a broader sense. Lines like “The map I drew” came from his own perspective. For this project, Hirai wanted to break new ground, so he decided on a concept album. He noticed how Machine Gun Kelly shifted to punk rock in 2020 while retaining hip-hop rhythms and syncopation, which showed Hirai that punk could still evolve.

That realization pushed the band to incorporate more syncopation into their work. Vocally, he also changed direction. Both he and Sawa had previously sung in a higher register, but for “Spiral,” Hirai dropped into a lower key using his natural male voice, driven by a desire to try things he had never attempted before. The guitar riff that opens the track is a deliberate nod to the intro of Sum 41’s “Heart Attack.”