While independently releasing three singles between 2020 and 2021, Nemophila garnered a sizable multinational following online by uploading videos to YouTube.

[1][2] In June 2021, British record label JPU compiled the singles into the internationally released Oiran: Extended Edition.

[3] She contacted her former classmate and bassist Haraguchi-san, and the two recruited former Soramimi drummer Tamu Murata through magazines and website posts.

[6] Nemophila played their first concerts on September 14 and 15 as part of Metal Weekend 2019 at Zepp Diver City, where they opened for Loudness and HammerFall.

[7][8] They released their first single "Oiran" on February 29, 2020, and held their first one-man live that same day to a sold-out audience at Shibuya Rex.

[11] On June 22, 2021, Kai of Esprit D'Air selected Nemophila as one of his top ten favorite rock and metal bands from Japan.

[13] Nemophila released their international compilation Oiran: Extended Edition from British label JPU Records on June 25.

[14] Compiling the band's entire discography up to that point, plus a new English version of "Dissension", it was the most pre-ordered album in the label's history.

[15] It also marked the first time the band's music had ever been available in record shops, as previously everything was sold directly from their website in Japan.

[16] Their first one-man concert with all five members at Line Cube Shibuya was performed on January 9, 2022[17] and the tickets sold out quickly after going on sale in October 2021.

[19] For each date of their first tour, which took place at various Zepp venues throughout June 2022, Nemophila was joined by one of the following acts; Mucc, Passcode, Loudness, Kishidan, or Rottengraffty.

[24] From May 31 to June 15, Nemophila held another Zepp tour where they were joined by a different act each night; Rottengraffty, Hanabie., Survive Said the Prophet, or Demon Kakka.

[27] On March 31, it was announced that Saki had left Nemophila due to "differences in direction" and that the band would continue as a four-piece.

[30] Nemophila had their first performance as a quartet at the 2024 Naon no Yaon festival on May 18, but their first standalone concert was held at Wild Side Tokyo on May 28.

[4] Mayu writes many of the lyrics, but the vocal melodies were primarily written by Akiyama and Saki, who took her suggestions into consideration.