From WoWWiki

The Undercroft is a crypt in the southwestern region of the Eastern Plaguelands. It is home to a band of undead trolls lead by the undead dire troll Zaeldarr the Outcast, who leads occasional raids on the Argent Dawn's Light's Hope Chapel to steal bodies from their grave pit. It is also the location of Tirion Fordring's ersatz grave.

Subzones of Eastern Plaguelands

Blackwood Lake • Browman Mill • Corin's Crossing • Crown Guard Tower • Darrowshire • Eastwall Gate • Eastwall Tower • The Fungal Vale • Hall of Arms • The Infectis Scar • Lake Mereldar • Library Wing • Light's Hope Chapel • Main Hall • The Marris Stead • Mazra'Alor • Northdale • Northpass Tower • The Noxious Glade • The Pestilent Scar • Plaguewood • Quel'Lithien Lodge • Scarlet Base Camp • The Scarlet Basilica • Stratholme • Terrordale • Terrorweb Tunnel • Thondroril River • Tyr's Hand • Tyr's Hand Abbey • The Undercroft • Zul'Mashar