The chainsword is a close-combat weapon shaped like a broad blade but edged with a spinning loop of powered, motorised teeth, much like a handheld chainsaw built for war. When its motor roars to life, the whirling teeth tear through armour, muscle, and bone, making it one of the most brutal and visceral melee arms in the Warhammer 40,000 galaxy.
Chainswords are widely used across many factions, but they are especially associated with the Space Marines and the assault troops of the human armies, who wield them in the savage press of hand-to-hand fighting. Because they are relatively simple to manufacture and maintain, they are far more common than exotic energy weapons, appearing in the hands of everyone from lowly gangers to elite champions.
The weapon comes in many forms. Smaller combat blades serve ordinary soldiers, while enormous two-handed versions, sometimes called chain-axes or great blades, are carried by hulking warriors and berserk fanatics. Ornate examples belonging to heroes may be decorated with skulls, purity seals, and honorific inscriptions. In battle the chainsword is as much a psychological weapon as a physical one: its shrieking motor and spray of debris are meant to terrify the enemy before the blade ever bites home.