Star Wars Animated Wiki

Darth Sidious (born Sheev Palpatine, also known as Emperor Palpatine) is the main antagonist of the Star Wars franchise, appearing in both Star Wars: The Clone Wars as the hidden main antagonist and the true secondary antagonist of Star Wars Rebels

From 2008 to 2012 he was voiced by the late Ian Ambercrombie, Tim Curry in 2013, Sam Witwer in Season 2 of Star Wars Rebels and Ian McDiaramid beginning in 2018. 

In The Rise of Skywalker, Sidious is revealed to be the paternal grandfather of Rey Skywalker