Lair of Infinite Agony is a new zone in Tiny Tina's Assault on Dragon Keep DLC
You will find a good horde of Skeletons waiting for you once you cross the threshold into this area.
Accessing Next Area
Head on forward to make your way toward the Temple of Misworship. As you approach the d20 chest, a shield will spring up around it and you will be assaulted by Skeletons. Get through the first few waves of Skeletons and you have Necromancers coming after you as well. There is a good chance of at least 1 or 2 badass sorcerers so be on guard there.