A Mana Vein is a plot device used in 8 bit theater. It effectively consists of a vein of Mana present in the ground much like a vein of gold or diamonds.
Over the course of the comic, King Steve insists on drilling for Mana despite it being impossible to obtain mana in such a manner as Left Hand Man Gary repeatedly states. Eventually on the penultimate comic in the entirety of 8 Bit theater, an actual Mana Vein is found.
- A Mana Vein could refer to the concept of Ley Lines. Ley Lines are channels of power which are often used as a plot device in the Fantasy Genre to explain how magic or the attraction of people to a place works.