Japanese singer-songwriter Eir Aoi is kicking off a new chapter with her latest single “MONSTER,” released under Lantis. The track has been chosen as the opening theme for the TV anime Classroom of the Elite 4th Season: Second Year, First Semester, which features a darker, more aggressive sound.

Combining her signature intensity with digital rock influences, “MONSTER” is written by Eir Aoi herself and draws inspiration from how protagonist Ayanokoji is perceived as a “monster” by those around him. Commenting on the opportunity, she shared, “I’m delighted to be singing the opening theme for Classroom of the Elite, a series loved by many people. I’m filled with gratitude for the opportunity to be involved in its production.” She added that the song explores a new side of her music while capturing the anime’s themes.

The single is set for release on April 22, 2026, in three editions—Type A, B, and C—each featuring “MONSTER” along with additional new tracks.