Millicas Gremory is next-in-line to the Gremory Clan after his aunt. He is the son of Sirzechs Lucifer and Grayfia Lucifuge, the nephew of Rias Gremory, and the grandson of Zeoticus and Venelana Gremory. Although his father was Lucifer of the Four Great Satans, his title does not apply to Millicas, as it was only required for Sirzechs and is not an inherent position, thus Millicas' family name is Gremory.
Millicas is a cute young boy with short crimson red hair inherited from his father, Sirzechs, and red eyes (blue-green in the anime) which he inherited from his mother, Grayfia.
Millicas is shown to be a well-mannered boy. Despite his young age, Millicas is shown to be very responsible even planning about his future peerage. He also prefers being referred as "Millicas" rather than "Millicas-sama" by the people close to him.
Millicas was born a few years before the start of the series.
Millicas first appeared in Volume 5 in the Gremory Castle to greet Rias when she returned to the Underworld. He later appeared alongside Issei when they were being tutored about high-class devils and the upper echelons of society and nobility by a private tutor, appointed by Venelana Gremory.
In Volume 10, he and his grandmother, Venelena Gremory, are shown to be visiting Issei and Rias after the two of them finished their Oppai Dragon Campaign. Venelena then scolds Rias for her lack of initiative towards her relationship with Issei before asking Issei to reconsider what he should call Rias in private. He and his grandmother then leave the two of them.
In Volume 13 short story "The Worry of the Next, Next Heir" (which takes place after Volume 12), Millicas goes to the Hyoudou Residence and lives with them. He later has a mock battle against Issei, Kiba, and Gasper. Despite losing to them, his power is extraordinary and his talent is said to be the same as that of Vali by Issei. During his stay, Millicas reveals that he wants to make a team like his father in the future. Later, when Sirzechs asked him whether he likes Satan Red or Oppai Dragon, Millicas chooses Oppai Dragon. This made Sirzechs sad, and it became worse when he sees Issei and Millicas getting along. At the end, Issei calls him Millicas instead of Millicas-sama.
In Volume 22, Millicas attended Rias's graduation ceremony, while also sticking close to Grayfia.
Powers & AbilitiesEdit
Demonic Power: As the son of Sirzechs Lucifer and Grayfia Lucifuge, Millicas possesses an incredible amount of talent which Issei compares to be at the same level with Vali. The rest of the Occult Research Club also commented that Milicas's control over his demonic powers was beyond what he should be able to do for his age.
- Power of Destruction (滅びの力 Horobi no Chikara): Like Sirzechs and Rias, Millicas also possesses the Power of Destruction inherited from his grandmother. Despite Millicas' young age, he has shown to have better control of his Power of Destruction than Rias, being able to shoot them like a shotgun as well as controlling its direction.
Enhanced Speed: During a mock battle with Issei, Yuuto, and Gasper, it shows that despite his small stature, Millicas can move at incredible speeds.
- Millicas' name is derived from the names of two characters from the Gundam TV series, Milliardo Peacecraft of Mobile Suit Gundam Wing and Casval Rem Deikun of Mobile Suit Gundam 0079
- Interestingly enough, the names used for Millicas' name is the real name of the characters used for his father's.
- In the Volume 13 Afterword, Ishibumi mentioned he would like to write a story about Millicas after DxD ends, as the main character who is all grown up attending a school in the Underworld.
- Millicas is a huge fan of the Oppai Dragon show.