The Serpent

The Serpent is a weapon developed by the League of Shadows.

History
After he was revived in the Lazarus Pit, Ra's al Ghul ordered Sensei to prepare the Serpent, but not activate it yet. Talia protested, but to no avail.

Background in other media
The Serpent, which lives in "the Garden", is an obvious reference to the Serpent that seduced Eve in the book of Genesis.