The Black Marsh is an Act 1 wilderness area that connects the Dark Wood to the Tamoe Highland. It contains side areas called the Forgotten Tower and the Hole.
Black Marsh belongs to the terror zone Black Marsh, Hole, Forgotten Tower and Tower Cellar. When it is terrorized in Hell, its monsters are 2 levels above your character, up to level 96, and give 25% more experience.
Black Marsh has super chests in its small houses. A super chest looks like a normal chest and always spawns on the same tiles. It ignores treasure classes and magic find: a 16-bit seed picks one of 65,536 fixed drop patterns, with a separate set for locked chests. Drops are all magic (95%) or all rare (5%), and some patterns contain high runes. See Lower Kurast super chests.