Marceline

Marceline the Vampire Queen is a major character of Adventure Time (2010-2018), a Cartoon Network series created by Pendleton Ward. She is an immortal, millenium-old, half-demon, and half-vampire woman with a playful personality. Unlike most depictions of vampires, who need to consume blood for sustenance, Marceline only needs to consume the color red (and other related hues such as pink and purple). She also likes to sing, and is a talented musician and songwriter; her signature item is the "Ax Bass", a heirloom battle axe converted into an electric bass. In the second season, she is revealed to be the daughter of Hunson Abadeer, the soul-eating ruler of a hell-like dimension called the "Nightosphere", and whom she has a strained relationship with. Furthermore, she later develops a romantic relationship with Princess Bubblegum; this same-sex romance was considered a landmark example in Western animation.

Adventure Time has fielded many Miss /co/ representatives throughout the tournament's history, but Marceline remains the only girl to have appeared in all editions, and is traditionally the series' most successful character and highest-seeded representative. However, she has low thread presence and little contest-related fanart, mainly relying on her show's recognition to win. Marceline first appeared in Ms. /co/ 2018 where she made her best result so far, a fourth-round loss to eventual champion Jenny Wakeman.

The vampire queen will next be eligible for Ms. /co/ 2022.

Results
Ms. /co/ 2018 - seed 12
 * R1: (117) Vampirella @ Vampirella 207 - 124 (62.5%)
 * R2: (76) Wilhamena Mettle @ OK KO 232 - 100 (69.9%)
 * R3: (21) Pacifica Northwest @ Gravity Falls 192 - 139 (58%)
 * R4: (37) Jenny Wakeman @ MLAATR 106 - 189 (35.9%)

Ms. /co/ 2019 - seed 40
 * R1: (89) Yumi Yoshimura @ HiHi Puffy AmiYumi 737 - 331 (69%)
 * R2: (25) Jinx @ DC Comics 617 - 567 (52.1%)
 * R3: (8) Velma Dinkley @ Scooby-Doo 507 - 718 (41.4%)

Ms. /co/ 2020 - seed 22
 * R1: (107) Spider-Gwen @ Marvel Comics 458 - 372 (55.2%)
 * R2: (43) Betty Boop  @ Betty Boop 453 - 380 (54,4%)
 * R3: (11) Hekapoo @ Star vs. The Forces of Evil 387 - 472 (45.1%)

Ms. /co/ 2021 - seed 20
 * R1: (109) Miss Valerie Frizzle @ The Magic School Bus 549 - 425 (56.4%)
 * R2: (45) Eris @ The Grim Adventures 368 - 530 (41%)