Walpurgis is the sixth studio album released by Aimer. It was released on April 14, 2021 in a regular CD only edition and in three versions: a limited CD + BD edition (Type-A), a limited CD + DVD edition (Type-B), and a Limited Edition CD + 3 BD edition. In addition, Walpurgis is Aimer's first album to be available in LP format.
Walpurgis peaked at No. 2 on Oricon's Weekly Album Chart dated April 26, 2021 and hit No. 1 on Billboard Japans Hot Albums and Top Albums Sales Charts dated April 21, 2021.