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PhD: Phantasy Degree, is a manhwa series created by Son Hee-joon. The series is published in English by Tokyopop. There are currently 10 volumes published, and the series' original publisher, Daiwon C.I. lists it as ongoing, but no new volumes have been published since 2005. A one-volume prequel to the series entitled Maejig Academy Zeus (매직 아카데미 제우스, Maejig Akademi Jeusu) was published in South Korea in 1998. In this series is a Succubus named Lady Notra.
A young, spunky, fearless girl named Sang is searching for the Demon School Hades. She runs into a group of misfit monsters who are all ditching classes from the same school. Sang convinces them to take her to the school ... and, since only monsters are allowed in, she 'monsterizes' herself by letting one of the misfits - a vampire - bite her. After the destruction of the Demon School Hades in volume 3, she moves on to search for more of "Satan's Rings".
The Lady Notra
A Succubus of royal descent. (They refer to her as Lady Notra in the series.) Notra seems attracted to a teenage demon named Dev in the series, but she also enjoys tormenting him. Despite her feelings for Dev, she is engaged to a white winged demon that a magician named Noel and her mother summon.