These unfortunate warriors gave their lives in battle only to be brought back into soulless servitude by arcane Orc magiks to fight for the Horde. Rising up from the battlefield, the Undead tirelessly hack and slash at their terrified enemies. These skeletal horrors retain none of the personality or emotions that permeated their living bodies and thus will do their master's bidding until they are destroyed. Only mortal creatures such as the Humans, Elves, Orcs, Trolls, and Ogres can be bound by these dark powers and be remade into the Undead.
They are weak and slow units that can be raised by a Death Knight's Raise Dead spell. They are therefore best used as a distraction or to cover one's retreat. They become more useful if there is no gold left on the map.
They are extremely vulnerable to the Exorcism spell of paladins.
Only living ground units (except Mages, Sappers and Demo Squads) can be raised as Skeletons - undead, ships, siege engines and fliers cannot.
They have a limited lifespan, and will fall apart after approximately 10 minutes on the default game speed setting. This does not apply to any Skeletons that are already present on the map at the start of the game.