Lapin

Her name, Lapin, means "rabbit" in French.

She possesses a carefree yet wicked personality—she treats corpses as playthings and delights in chaos.

Despite her cruelty, Lapin genuinely loves her younger sisters, and they deeply love her in return.

Lapin became a magical girl by wishing to "bring mother back to normal," after her mother, Isabeau de Bavière, turned into a witch.

As a result of this wish, Lapin has a unique magical ability:

Even if she becomes a witch and is defeated, she will revert to being a magical girl instead of dying.

Both in her magical girl and witch forms, Lapin uses a special object called the "Magic Eye," which allows her to cancel the transformations of other magical girls.

Lapin is manipulated by Minou, who tells her that Corbeau was killed by Tart and her companions.

Furious and seeking revenge, Lapin attacks them relentlessly.

With her nearly immortal ability, she becomes a serious threat to Tart and her friends.

Eventually, Riz Hawkwood seals both herself and Lapin away into the realm of shadows.

This act finally puts an end to Lapin's rampage, despite her seemingly unkillable magic.