The X-Men and the Micronauts #3 (1983)

Mine Eyes Have Seen the Glory!
On Earth, Xavier has fallen into a kind of coma, psychically experiencing how the brainwashed X-Men and Micronauts slaughter Karza’s soldiers in the Entity’s name. They do try to hold back as much as possible, though, with the exception of Kitty (really Baron Karza), whom the Entity promises to reward for that, after he kills the rest of the soldiers and destroys that world. The other X-Men and Micronauts are thrown into a dungeon. After Colossus prevents Wolverine from killing them all, they decide to fight the Entity, no matter how slim the hope may be. The Entity intends to seduce kitty but sends his astral body out, sensing that Xavier has escaped his sleeping body. Karza (in Kitty’s body) uses the opportunity to stab the Entity’s body in the back leaving him for dead. On the astral plane, Xavier and the Entity face each other and Xavier is horrified to learn that the Entity is part of himself – his own dark side that now has a life of its own. The Entity wins and takes over Xavier’s body. On Homeworld, Kitty, trapped in Karza’s body, is now free to act but doesn’t yet know what to do.
Release Date: 1983