- Since Windu was heavily blasted with force lightning, it would be rational to conclude that he is dead. However, seeing as he is a Jedi with connections to the Dark side, he may have had abilities that the Jedi order were oblivious to and he was also an extremely high ranking member of the council, second only to Grand Master Yoda. So given all the evidence, it is probably that he is alive, but after the events of Order 66, he went into exile. After the Empire eventually disbanded, he likely went back to Coruscant or his home planet, but stayed out of sight to avoid sightings in a possibly still hostile galaxy.
Is Mace Windu really dead?


Force lightning does not normally kill. Since he is a Jedi, he could have slowed his fall. He only lost his hand to Anakin. It is reasonable to assume he is still alive.

He did have connections to the dark side. Like maul and Anakin, dark side anger can keep you alive even after great injuries.

We do know that in Star Wars The Rise of Skywalker, Mace Windu spoke to Rey through the force, along with Ashoka and Qui-Gon-Jin.He is dead now, but he still could have survived longer than it seems until that point.
Alive