Yagba - Witch Queen of the Mire

Yagba came to the Greenwold ages ago - a powerful fiend from the fire-blasted salt plains of Gehenna - choosing the dark swamp of the Starless Mire as her home. The sly hag made her arcane knowledge available to the primitive mire dwellers, becoming mentor to druids, warlocks and witches, while making the swamp hospitable to the hags - securing her position at the top of a hierarchy of covens. Yagba does not easily reveal her fiendish nature, concealing her true identity (and true name) behind centuries of obfuscation and lies. The only threat to the witch came when Sabal the Black brought her brood to the mire, setting the two into a stalemate that has lasted for centuries.

A Yugoloth and a Witch?

Ancient lore claims that Yagba began life as one of the first yugoloth created by the night hags who spawned that race. She learned from those ancient sisters, becoming much like them. When war caused the Books of Keeping to be lost, Yagba disappeared with one, - bartering with a forgotten king of the Greenwold to be summoned into this realm. When he demanded the tome, she transmuted each page into a snake, which slithered off into the Starless Mire. Descendants of those snakes crawl the swamp still, fragments of true names visible as runes in the pattern of their scales