The Night Shade of Greyhawk and the Hallowed Revenant Amphoras
Conquer and destroy.
Let your strength crush the weak.
Do as you will, and let no one stop you.
Gruumsh appears as a powerful orc with one eye. A figure of fury and driven cruelty, Gruumsh rules his pantheon with brute power. His favored weapon is the spear.
Gruumsh is the husband of Luthic and father of Bahgtru. Ilneval is his most capable lieutenant.
Gruumsh considers himself supreme, and considers every non-orc his enemy, holding special enmity for some. Gruumsh hates Corellon Larethian with a passion, because he lost his eye to Corellon in battle. He spreads this hatred to all of the Seldarine, especially Sehanine Moonbow, who fooled the orcish god many times to protect Corellon and her other family members. Gruumsh also loathes Moradin and the dwarven pantheon.
In his own pantheon, Gruumsh rules over all the other gods (although Shargaas and Yurtrus bear him little real loyalty beside that made from fear), and has his orders carried out through his lieutenant Ilneval.
Gruumsh's divine realm is the Iron Fortress in Nishrek. In the standard cosmology represented by the Greyhawk and Planescape campaign settings, Nishrek is a part of Acheron, while in the Forgotten Realms cosmology this is a plane of its own.
Gruumsh shares his home in the Iron Fortress with his son Bahgtru and his lieutenant Ilneval.
As orcs that are not clerics or adepts are forbidden to speak his name, Gruumsh is also known as "One-Eye," "The One-Eyed God," "He-Who-Never-Sleeps," and "He-Who-Watches."
Clergy, temples, and rituals
Gruumsh's priests wear dark red vestments, war helms, and black plate mail. His sacred animal is the giant rat. His holy day is the new moon, and he is worshipped in orcish lairs. A sacrifice of blood is made to him monthly.
Myths and legends
In a past time, Gruumsh had two eyes but he lost one in a fight with the chief elven god Corellon Larethian. Gruumsh meant to paralyze Corellon with his magical spear; this attack failed and initiated an epic battle. During the course of this battle Gruumsh injured Corellon and, according to legend, from the blood shed the elven people were created. Corellon ended the fight by putting out Gruumsh's left eye, which is how Gruumsh earned his moniker "One-Eye." Some orcish clerics deny this tale, dismissing it as elven propaganda, and claim that Gruumsh always had one eye.
Gruumsh created the orcs in his image to be his servants in the world but was cheated out of a home for his people by the other gods, according to the following excerpt by Roger E. Moore (from Unearthed Arcana):
In the beginning all the gods met and drew lots for the parts of the world in which their representative races would dwell. The human gods drew the lot that allowed humans to dwell where they pleased, in any environment. The elven gods drew the green forests, the dwarven deities drew the high mountains, the gnomish gods the rocky, sunlit hills, and the halfling gods picked the lot that gave them the fields and meadows. Then the assembled gods turned to the orcish gods and laughed loud and long. "All the lots are taken!" they said tauntingly. "Where will your people dwell, One-Eye? There is no place left!"
There was silence upon the world then, as Gruumsh One-Eye lifted his great iron spear and stretched it over the world. The shaft blotted the sun over a great part of the lands as he spoke: "No! You Lie! You have rigged the drawing of the lots, hoping to cheat me and my followers. But One-Eye never sleeps. One-Eye sees all. There is a place for orcs to dwell…here!," he bellowed, and his spear pierced the mountains, opening a mighty rift and chasms. "And here!," and the spearhead split the hills and made them shake and covered them in dust. "And here!," and the black spear gouged the meadows and made them bare.
"There!" roared He-Who-Watches triumphantly, and his voice carried to the ends of the world. "There is where the orcs shall dwell! There they will survive, and multiply, and grow stronger, and a day will come when they cover the world, and they will slay all of your collective peoples! Orcs shall inherit the world you sought to cheat me of!"