Diirinka

Diirinka was the god of the derro, monstrous hybrids of dwarves and humans that inhabited the Underdark.

His symbol was a spiral of gray, black, and white.

He was a deity of magic and knowledge, as well as cruelty. He resided in the realm called the Hidden Betrayal on Pandemonium's layer of Phlegethon.

Origins
Diirinka was thought to be the son between Moradin and Berronar Truesilver as well as the brother to Abbathor, Clangeddin Silverbeard, Sharindlar, Vergadain, Thard Harr, Gorm Gulthyn, Marthammor Duin, Dugmaren Brightmantle, Laduguer and Diinkarazan, in the case of the latter twin.

He was banished by his father alongside his brother, though it wasn't clear for what.

It should be noted that Diirinka might not exist, as the truth behind the Derro's origins was that they were a form of dwarves tortured into insanity by the illithids. Though interestingly, worship of entities called Diirinka and Diinkarazan existed in Old Shanatar.