Count Dooku
Count Dooku does not directly appear in the seventh season. However, as the events of "Revenge of the Sith" are concurrent with the season's final arc, Ahsoka Tano is informed of his demise at Anakin's hands by Obi-Wan, who tells her that it is important to capture Maul, being the only way the Jedi can discover the true identity of Darth Sidious after Dooku's death.