The orcs love bloodsports, everyone knows that. If you go deep enough into their lands, you will find their favorite entertainment is the Talbar, the arena.
The idea of using tattoos to contain magic powers is not a new one. The Ink gauntlet follows the basic premise of using rare and precious inks to inscribe spells into the skin of a mage or would be spell-imbued person. Some of these inked spells might be permanent, while others might fade after being used once, or a preset number of times.