Mikarin is an idol of the Survey Corps appearing in the gag preview of Volume 10 in Volume 9 of the Attack on Titan manga.
Mikarin is a fairly tall, physically fit, and very muscular teenage girl with chin-length black hair. Her body is extremely well-toned, with little, if any, in the way of body fat along with muscles lined throughout her arms, legs, and abs. Mikarin also has a small scar below her right eye.
Mikarin possesses a single-minded sense of resolve and has a particular interest in Eren. However, she is prone to doing surprisingly rash things like trying to immediately cut down people she does not like.
Appearance: Mikarin is a fairly tall, physically fit, and very muscular teenage girl with chin-length black hair. Her body is extremely well-toned, with little, if any, in the way of body fat along with muscles lined throughout her arms, legs, and abs.
Personality: Mikarin possesses a single-minded sense of resolve and has a particular interest in Eren. However, she is prone to doing surprisingly rash things like trying to immediately cut down people she does not like.
Abilities: As the most powerful member of the Survey Corps Idol Unit, Mikarin is a singer and dancer of devastating talent, capable of mesmerizing even the Titans. Her toned musculature speaks to her physical strength and prowess, the key to her blood-splattering dance masterpiece of a career.
Source: Attack on Titan Wiki, available under CC BY-SA 3.0.