Sanguini was a vampire who attended a Slug Club Christmas party during Harry Potter's sixth year at Hogwarts School of Witchcraft and Wizardry. He was the guest of Eldred Worple. The tall, emaciated man had dark shadows under his eyes and looked bored with the party until a nearby group of girls attracted his attention. Worple tried to distract him from the girls by shoving a pasty into his hand.
The name Sanguini most likely originates from the Latin word sanguineus, meaning "of blood", "bloody", "blood-coloured", or "bloodthirsty" - a reference to his vampirism. The Latin word sanguini is the dative singular of the noun sanguis, "blood", and means literally "to blood" or "for blood." Other possible influences derived from this Latin root include French sang and Italian sangue, both meaning "blood", and the English words exsanguination, "to bleed out", and sanguine, describing a blood colour or having an active, warm and lively circulation or temper.
Behind the scenes
In the film version of Harry Potter and the Half-Blood Prince, scenes with Sanguini (portrayed by British actor Charlie Bennison) were shot, but were cut from the final edit of the film. In one photo he is seen with Eldred Worple talking with Luna Lovegood. Sanguini can be seen in the background on close observation.