Devil's Bane is the first Sea-Prism Stone sword that was added to the game and is one of only 2 swords alongside the Waverunner sword that can hit Logia users. Wielders of this sword cannot hit Chop-Chop users. 

The only way to get Devil's Bane sword was to join One Piece Golden Ageduring the first hour of release.

Devil's Bane is no longer obtainable

The durability regenerates after being damaged.

After OPGA update v2.5 (OPGA2) Devil's Bane will be removed