Marina Inoue
The season features five pieces of theme music: four opening themes, and one ending theme. , the ending theme, was composed by Alisa Takigawa and Saku, written by Takigawa, and performed by Takigawa. All of the opening themes were composed by Mito and written by Meg Rock, and 3/4 of them feature vocals by members of the cast. The first opening, "decent black", was sung by Kaori Mizuhashi (Ougi Oshino); the second opening, "mathemagics", was sung by Marina Inoue (Sodachi Oikura); the third opening, , was also sung by Marina Inoue; and the fourth opening, "mein schatz", does not feature any of the cast's vocals.