From WoWWiki

The Infectis Scar is a deep pitfall in the blighted earth of the Eastern Plaguelands. Unlike the Pestilent Scar, which is a natural gorge (possibly a dried-up lake of some kind), the Infectis Scar is the result of dark magic. When his runesword was broken against the shield of a dwarf captain near Corin's Crossing, the death knight Marduk Blackpool discarded the blade and kept the hilt with him. The evil blade sunk into the earth, creating the chasm that exists today.

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