The Chainsword is a Hardmode weapon that is both a Sword and an Axe. It can be dropped by The Motherboard.
Tooltip: "It looks lika a sword, but it is actually an saw! Buy yours today!"#
- This may be a reference to Warhammer 40k's melee weapon used by Space Marines and Chaos Space Marines that goes by the same name. It also bears a striking resemblence to the sword in WH40K.