The song "Red and Blue" was originally composed by Silentroom, then known under the alias "Polycube" for Sound Voltex III: Gravity War's "The First VOLTEX Character Theme Song Contest" in 2014. However, the song was unable to be submitted due to missing the deadline. It was later added and repurposed for Arcaea in the 1.5.0 update.

As part of "The 8th KAC Original Song Contest", several artists affiliated with independent music label HARDCORE TANO*C collaborated on a song known as "BATTLE NO. 1". However, the song was rejected from the contest. It's theorized this was due to the artists being credited as "TANO*C Sound Team", a jab at the controversial "BEMANI Sound Team" rebranding of BEMANI's internal composers. "BATTLE NO. 1" would later be featured in other rhythm games such as WACCA, Arcaea, and the Maimai series.