Once the Champion returns with the Great Sigil Stone, Martin will prepare for the ritual to open a portal to Gaiar Alata - Mankar Camoran's Paradise. The Champion will be asked to prepare and talk to Martin when he is ready. You are given the opportunity to walk freely inside the Bruma stronghold at this point, however there is very little for a player to do besides manage the Champion's inventory. The Champion is unable to interact with anyone except Martin. Once speaking to Martin again, he will start the ritual and wish the Champion luck.
After the ritual, the Champion is transported to Camoran's Paradise. It is a small, single level map, with merely two Mythic Dawn agents. All a player must do is effortlessly navigate the winding path to Camoran's Palace to the west.
Upon the Champion's arrival, Camoran will explain that it is too late for Tamriel and that Mehrunes Dagon's arrival into Tamriel is inevitable. The Champion must then face him. Upon defeating Camoran, the quest will end and the Champion will be returned to Bruma with the Amulet of Kings.