From Pixiv creator DC Ultra, whose works follow the story of university student Anna Blackthorn, who has taken on the burden of being her planet's hero, Ultra.

This features Moto, a new friend/rival for Anna, and a new teacher Ms. Spectre, who unveils her own alter ego and powers as "the Ghost" when investigating the disappearances of some university girls. Gallery contains The Ghost, Costume Day Part 1 (which starts on page 164), and Costume Day Part 2 (which starts on page 335)

(See all works at):
https://www.pixiv.net/en/users/13098329

Vol 1: https://e-hentai.org/g/2808388/797d828c62/
Vol 2: https://e-hentai.org/g/2811481/5f0133ec90/
Vol 3: https://e-hentai.org/g/2813836/4619fdd99c/
Vol 4: Here