Breath of the Wild
The swamp is situated just northeast of the Dueling Peaks Stable, on the west side of Blatchery Plain. It is a marshy terrain with small ponds and old ruins found throughout the area. The swamp is littered with inactive guardians, although there is a single Decayed Guardian to the northwest that will come alive when Link draws near.
In the center of the Swamp, Link can find the Recovered Memory titled Zelda's Awakening. This clip shows Link doing battle with guardians during the Great Calamity. It is here that Link fell in battle and Princess Zelda's power was awoken, defeating all of the guardians in the process. Two Sheikah Guards appeared, and Zelda instructed them to take Link to the Shrine of Resurrection.
The Ash Swamp has several Bokoblin in the area, including a Bokoblin Camp just to the northeast. The Bokoblin Camp has a treasure chest that contains an Opal gem. At the south end of the camp, the Bokoblin can be found guarding a treasure chest with a Double Axe, as well as several Traveler's Claymores that are in the ground. Two more treasure chests can be found to the west, one containing some Fire Arrows, with another having an Emblazoned Shield.