Chainsword

From Lexicanum.com:

Chain Weapons are close combat weapons which utilize a cutting chain mechanism (similar in principle to a chainsaw) along the length of the striking edge. They are most effective in assaults against lightly armoured targets and are generally used in wide sweeping attacks to make full use of momentum for maximum impact and cutting strength. Several armies make use of Chain Weapons, including the Imperial Guard, Space Marines, Chaos Space Marines and Eldar.

Occasionally they are used as an attachment to another weapon; a small chainblade can sometimes be used as a form of bayonet attached to a ranged weapon to aid in close combat.

 

A Chainsword is a common form of chain weapon which is essentially a sword with powered teeth that run along the blade like that of a chainsaw. Most versions make use of monomolecular-edged or otherwise razor sharp teeth. The weapon makes an angry buzzing sound as the teeth spin around, intensifying into a high pitched scream as they grind into armour.

 

Teeth from Pack.Rat.

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