Percier is an original character exclusive to Metal Slug Attack.
A small girl with green hair, she considers herself to be the "eternal assistant" of the Professor. She didn't share his interest in Martian technology, however, and he abandoned her while leaving the Rebel Army.
She looks and acts like a Martian, as her infobox states that it is a way to compete with for affection from the Professor. She dislikes the Martians (out of jealousy) because they "stole" her "beloved". The Professor considers her to be somewhat boring.
Percier appears in the story "For You", where she appears being chased by rebel soldiers. Upon being saved by the Professor and his allies, she tries to act like a Martian, but the Professor's Martian comrades do not understand what she is saying. The Professor recognizes her easily through her disguise, and having no point in leaving her this time, allows her to tag along. During this story, her relationship with the Professor is shown, and she also becomes "friends" with Marty.
- Along with Heidern, she is one of the few purchasable units that makes a cameo before their debut.
- Upon victory, she typically plays upon a Neo Geo Pocket with a wireless unit attached. Her large hood hides an ahoge.
- If the Professor is in the same deck as her, this changes to where she thinks about the Professor.