"Reach Dragon Keep" is a mission objective in the quest A Game of Games in Tiny Tina's Assault on Dragon Keep DLC.
Walkthrough[edit]
Head on forward and take the elevator up in front of you. Once there start on over to the left and take the stairs there upwards. From there it is a simple matter of fighting your way on through a horde of Skeletons, mages, knights and the occasional dragon.
Make it to the blue portal on the ground then step into it to come to face the Handsome Sorcerer.