First go to Soul War and enter the teleport with Infernal Demons

Then find and light five statues on floor -3 to open the near gate

In the next part you will need 5 people
Four people to seize sqm and the last person to enter the portal to open the way

The next part is to find and move five levers to open the entrance

You started the first of the five seals. At the end you will face a boss

You need five people to fight the boss
Four people to stand on sqm and one to activate the boss
You do it four times. One for each seal

Team is moved to the next room after 1 minute
The next room is more difficult. Warning of a lot of Infernal Demons!

Last seal with lots of Many Faces

Last fight with Mutated Oberon

Just rewards