Presence

The presence was a voice heard by Ezra Bridger on Malachor when he used a Sith holocron to activate the superweapon of the subterranean Sith temple. Ezra was led by Darth Maul to believe using the holocron would grant the knowledge to destroy the Sith, but the presence informed him the knowledge was the power of the temple's battle station, and that if he would not use its power, perhaps the approaching Darth Vader would.

Behind the scenes
The presence was voiced by Nika Futterman, who portrayed Asajj Ventress on Star Wars: The Clone Wars. According to Star Wars Rebels executive producer Dave Filoni, the presence was the voice of the Sith Lord who created the temple. Filoni gave the character a name, but he would not reveal it until he had checked with other members of the Lucasfilm Story Group for approval.