What is the death eater in Harry Potter?

Mbth Death Eaters, the organization in the magical novel Harry Potter and the title of Voldemort's henchmen are all supporters and believers of the Dark Lord. They all branded their left arms with dark marks and were proficient in dark magic.

Physical characteristics:

They all branded their left arms with dark marks and were proficient in dark magic (taught in part by the Dark Lord). When the Dark Lord touches dark mark on one of the Death Eaters, what will dark mark of the other Death Eaters feel? At this time, they will immediately apparate, appear beside Voldemort and obey orders.

When a death eater touches dark mark branded on his left arm, Voldemort can feel the call and apparate himself or her. In the last movie, if Harry is summoned without controlling him, they will be punished by Voldemort's piercing spell. But after Harry entered Hogwarts, Voldemort was ecstatic when he was summoned, and immediately called all the death eaters he could to attack Hogwarts.