Yumisu from The Demon Queen R (A remake of Overthrow! The Demon Queen), a game by JSK Studios.JSK visited the Demon Queen concept a couple of times (examples <a rel="ugc" href="https://prnt.sc/3YPVsQuF526x">1</a> and 2), though Yumisu remains my favorite of the bunch.

Demon Lord Yumisu - The Demon Queen R (JSK Studios)

1girl, solo, yumillusu, demon girl, grey hair, long hair, red eyes, slit pupils, pointy ears, horns, purple skin, facial mark, armor, floating armor, gorget, crop top, large breasts, bare shoulders, elbow gloves, vambraces, navel, pelvic curtain, thighhighs, armored boots, black shoes,

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