Guldo

Guldos are an enemy species in Xenoblade Chronicles 2. They are humanoid zombie-creatures embedded with Core Crystals. The only way to kill a Guldo permanently is to destroy their Core Crystals. Guldos have the unique ability to absorb a 's element during battle.

Xenoblade Chronicles 2
Guldos are found exclusively in the Land of Morytha. Two types of Guldos can be found, a smaller type and a much bigger type that is fought exclusively as a boss and quest-exclusive enemy.

The Architect reveals that the Guldos were originally human survivors from his world after the Conduit's activation. They used Core Crystals to replace their brain cells in an attempt to survive. This resulted in them mutating into horrible abominations.