Albertine

Albertine is a witch villain from Puella Magi Madoka Magica. She doesn't appear in any anime episodes but she appears in Madoka Magica Portable and Magical Crusaders Mategi Magica as a boss. Her familiar, Anja, makes a brief appearance at the end of Episode 5.

Albertine is the scribbling witch (has not debuted), with an ignorant nature. She loves Hide and Seek. However, because none of her minions are very intelligent, none of them seek her out.

In Puella Magi Madoka Magica Portable
Albertine is finally revealed in Puella Magi Madoka Magica Portable. She is shown to be able to create different Anja familiars by drawing them on the ground. An official article from Dengeki Playstation suggests that she could have come from the Anja familiar from Episode 5.
 * She only appears in the mysterious witches barrier "Fool's Barrier," which is unlocked by completing Sayaka's route. In the game routes, only her familiars are present.
 * She occasionally hides herself in building blocks. To make her reappear, just attack the building blocks in her barrier.
 * She may begin to cry when suffered attack. Your magical girl can't attack her when she cries without Negate Spec. Stat Effects ability.

Trivia
In BD commentary for Episode 5, Anja was voiced by Aoi Yuuki (Madoka).