Undefeated Matriarch of the Gouyoku Alliance
Toutetsu Yuuma is the main antagonist and final boss of Touhou 17.5, Gouyoku Ibun ~ Suibotsushita Chinshuu Jigoku (Strange Tale of Avarice ~ Submerged Hell of Sunken Sorrow), first mentioned in Wily Beast and Weakest Creature.
As her title suggests, she's the boss of the Eagle Spirits. She has large red, sheep horns, with a horn ribbon on both horns. She has curly, white hair, red eyes with horizontal, rectangular pupils, and is often depicted with sharp teeth. She wears earrings on her pointy ears.
She wears a blue dress with detached, red sleeves. Her clothing has a meandros pattern with eye prints. Some artists may depict her wearing a blue vest and blue_skirt instead. She often goes barefoot and carries around an oversized spork which may be filled with petroleum or blood. Her spork may be depicted as a spoon by some artists, either deliberately or as a mistake.
Her ability allows her to devour and absorb almost absolutely anything, turning it into her power. Unlike her fellow Animal Realm matriarchs, she and her organization prefer to avoid pointless conflict, and would rather recruit or forge a mutually-beneficial relationship with their enemies, with an all-out war being a last resort for them. Taking advantage of the events in Wily Beast and Weakest Creature, she went to the Former Hell of Blood Pools in order to monopolize the petroleum deposits there, containing the desires of long dead organic beings.
Note: If you can't concretely identify the utensil she is wielding (even with the tags/title/commentary/parent-child posts/pools), just tag utensil instead.