Also known as: YZY姉貴, MSTA姉貴, MSTA, クソデブ姉貴
Voice of Koakuma and Mystia Lorelei and artist in the original Cookie☆. While sometimes treated as two separate characters, they almost never interact so this wiki chooses to combine them. Also called Fucking Fat-aneki based on a followup video by Hazuna Rio so she became associated with Sumo wrestling.
Running jokes include her flapping her arms, asking for hot water, her distinctive wave greeting, and constantly fleeing as Mystia.