The "Doomsday" plot leak also seems to confirm the big fight at the X-Men mansion in the universe where Monica Rambeau ended up at the end of "The Marvels." That universe's anchor being is a Professor X (Patrick Stewart) variant that Doom wants to kill. Interestingly, Earth-616 and Earth-10005 -- where Monica is -- are on a collision course.

First Steps" has a thrilling ending that teases Dr. Doom and where the MCU goes from here in "Avengers: Doomsday."

Marvel’s Fantastic Four are finally in the MCU, and they’re not wasting any time jumping into the action. After their debut in The Fantastic Four: First Steps, the team is set to appear in the upcoming Avengers: Doomsday,