Marvel: Ultimate Alliance/Mephisto's Realm

After the cutscene, your team is tasked to find Nightcrawler in this world of hell. During this part of the mission, Jean Grey will help you in your quest to creating a shield around Nightcrawler.

The Five Challenges
You have 5 challenges to contend with before you go into the middle to teleport. Doing all five challenges opens the middle portal to another section in the game.
 * 1) The first challenge involves throwing the enemies into the lava pit in the middle. It would be easier to command your team to defense so that the enemy will come to you and allow you to throw him in with ease. As soon as the command reverts to normal, keep it on defense until the portal is lowered.
 * 2) The second challenge is to destroy the enemies stone grave to open another portal.
 * 3) The third challenge is quite easy. After you defeat the enemies, it opens to the torch you are going to use to light up the four cups in that area to open another portal.
 * 4) The fourth challenge involves destroying the three trees in the middle with an axe, destroy the flying enemies to open another portal.
 * 5) The final challenge is a little hard. You have to attack the enemies in the middle of the circle to open another portal.

Free Night Rider
Once you teleported to the next section, Jean Grey would be captured, raising the stakes even further. You'll encounter Night Rider for the first time as his lying in the middle. You have to defeat the Fire Giants and the other enemies before you break the chain marked with an "X". Do it to all four "X"s. Then after the exchange between Thor and Mephisto, you need to swap with one of your team. You can exchange with anyone but the superhero you should swap over until the end of this mission is Spiderman. The reason simply that he's strength is nowhere as strong as the other members of the team, as long as you still have your default team.

Blackheart Madness
You'll be teleported again until you reach Blackheart. He's much tougher than Mandarin with his energy attack. If you seriously want to take down this boss more quickly, use the spear to destroy the chambers where he's resurrected which can take some doing if you get too close. If you don't destroy those chambers, Blackheart will resurrect three more times and he will wear you out.

Heartbreaking Decision
After a climactic fight with Blackheart, you go up to two cages which is about to drop. Both Nightcrawler and Jean Grey can't get out until you free one of them. Afterwards you'll teleport to the Stygian Abyss.

You'll have a climactic battle with Mephisto's minions which will take a while until they are all defeated. Once you go in. Your team confronts Mephisto. He'll have one last puzzle before the climactic battle. The one who died will appear like statues you need to destroy with a sword. But you need to get it off Mephisto. Get ready to grab the weapon by blocking, allowing you to use his sword to destroy it. Do it on all five statues and the one who dies will be part of the final confrontation. This battle would be quite hard because one of Mephisto's attack would force you to go on the opposite direction and you have to run all the way back and continue attacking him. Once his health bar turns blue, turn to the companion and attack it. But the ones mind reverts back and sacrifice itself into defeating Mephisto.

You'll return to Sanctum Sanctorum through the portal. Nick Fury will tell you since Loki and his gang attacked Asgard, the team will move to Valhalla to continue on the mission.