Thanos was able to wipe out half of all life in the universe in Avengers: Infinity War, as the Avengers weren't strong enough to stop him in time. It won't be as easy for Thanos to pull off his infamous click in Marvel Ultimate Alliance 3: The Black Order, as the X-Men will be opposing him and they have just been joined by several new mutants.
The fate of the universe is hanging in the balance, as Thanos intends to use the Infinity Stones for his own nefarious purposes. It's due to the arrival of this new enemy that Magneto has decided to lay down his enmity for the X-Men and join the Marvel heroes in trying to stop the Black Order.
The new trailer confirms that several new characters will be joining the roster, which includes Magneto, Nightcrawler, Psylocke, Scarlet Witch, and Deadpool. They will be joining the likes of the Avengers, Captain Marvel, Dr. Strange, Guardians of the Galaxy, Ms. Marve,l and several different versions of Spider-Man in their battle against Thanos and the Black Order.
There are several villains who are cool with Thanos' plan to wipe out half of all life, as Juggernaut will be a boss in the game. It seems that the Juggernaut will be fought in a special battle where he chases the player's team through the stage, which is similar to a level from the first X-Men: Legends game, where the player is pursued by Juggernaut through the X-Men's mansion.
The previous Marvel Ultimate Alliance games featured playable versions of villains, with Doctor Doom, Sabertooth, and Venom being playable in the first game, and Juggernaut and Magneto being playable in the second. Magneto is known for his hatred of humanity, but if Thanos completes his plan, then half of all mutants will also be wiped out, so it makes sense that he would take up arms against the Black Order and temporarily side with the X-Men, as he has done in the past against foes such as Apocalypse.
Marvel Ultimate Alliance 3: The Black Order will be released for the Nintendo Switch on July 19, 2019.