This one of the very few dungeons with creatures that drop Tier 7 Loot. There is a portal to the Mhoire Castle Great Hall at the drop that can be entered after completing the three tasks Shade of Antemy gives you. There are four portals to this dungeon arrayed around the Mhoire Castle Courtyard which floats over graveyard. You must complete a flagging quest to gain access, see Castle of Lord Mhoire Quest for details. Initially you can only use the Mhoire Castle Northeast Tower portal, however after completing a trial in a tower, you are flagged to use that tower's portal from the courtyard.