T o be more precise the place is called "endless infernum".
It is the place where u enter a door to fight the giant worm.But after getting the "soul of steel", go to that door but do not enter it.
Jus oppositte to the door u will not find any way but jus a huge gap between the other side and u.Now that u have the soul of steel jus walk across it and u will not fall into the gap.Thenu place the soul of steel in the door to open it.Dont forget to break a combat Adjucator to ur right before u enter the door.u will get a blue orb.it will break if u hit it with cerebrus(it will break when ur rage meter(dope-blast -sweet-showtime) is high enough).