Nathan Agrippa

Nathan is quiet, unsettling in appearance, intelligent, and fundamentally benevolent. His habit of mumbling causes visitors to misread both his words and intentions, much as Gordon's social difficulties do.

Unlike earlier generations of the Agrippa family, Nathan does not want its knowledge of curses to remain associated with killing. He deliberately studies old experiments so that their results can be converted into treatments and cures.

His scientific curiosity can still appear alarming. When examining Asta, Nathan extends unnatural-looking black nails toward him without clearly explaining what he intends to do, terrifying the visiting Black Bulls before revealing that he is checking Asta's physical condition rather than attacking him.

Nathan uses Black Oil Magic, generating and manipulating supernatural black oil.

Through Creation Magic, he shapes the oil into specialized tools such as Curse-Filled Nails and ritual implements.

His Curse Candle Ritual Disk allows him to detect concentrations of curses across a broad geographical area. When the Black Bulls ask him to help investigate devils and Forbidden Magic, the technique reveals an exceptionally powerful curse located in the Heart Kingdom.

Nathan's most significant expertise is medical and occult rather than offensive. He combines centuries of Agrippa family records with experimentation designed to diagnose and treat curses.

Nathan is first referenced when Gordon seeks help for Asta's damaged arms. He cannot remove the ancient curse affecting them and declines the request, though Gordon initially misunderstands the refusal.

Later, Gordon returns home with Asta, Gauche Adlai, and Grey while investigating devils and curses.

The visitors initially interpret the Agrippa household as sinister because of its appearance and history. Nathan then explains that he has deliberately redirected the family's research toward healing people instead of harming them.

He uses his curse-detection ritual to map powerful curse activity and identifies the Heart Kingdom as the location of an unusually severe curse. That discovery helps direct the Black Bulls toward Lolopechka, Megicula, and the larger devil threat.

Gordon Agrippa is Nathan's son. Nathan takes an active interest in Gordon's Poison Magic and later helps him adapt the family's curse knowledge toward healing and support.

Jonna Agrippa is Nathan's wife. The two meet when Nathan is eighteen and later build the current Agrippa household together.

Roxanne Agrippa is Nathan's daughter and Gordon's younger sister.

Nilenia Agrippa is Nathan's mother and a member of the older generation associated with the family's history of curses.

Asta becomes one of Nathan's examination subjects when the Black Bulls visit seeking information about devils.

Gauche Adlai and Grey accompany Gordon and Asta to the Agrippa home and initially mistake Nathan's medical behavior for an attack.