To sum up, an orc tribe that was on the rocks prayed to Gruumsh. In return they received the Sanguine Grail: an artifact that allows the orcs to, painfully, extract powers and knowledge from their victims.
"More fire! More fire! When I dance, the flames dance with me. They burst out when my feet strike the ground. They spurt from my fingers. They snake around my hips. It's the most beautiful dance in the world.