Curse-Filled Nails

Black Oil Creation Magic: Curse-Filled Nails (黒油創成魔法『呪尽爪』) is a black oil-based Creation Magic spell.

Description
With an open grimoire, the user shapes black oil into long fingernails on one of their hands. Upon contact with a person, these fingernails allow the user to sense the person's physical condition, including body temperature and magic power.