Mirrodin common. A common design method for coming up with new cards is looking for effects that can be mirrored in other colors. While designing Mirrodin the team wanted an effect like Soul Warden but for artifacts, and so Leonin Elder was born. After that, Disciple of the Vault was an obvious next step as a mirror, but this pair of cards shows just how different life gain and life loss are in terms of power.
