Wanda

Wanda is a fairy who first appeared in the Japanese-only Super Famicom game Mario & Wario. In the game's storyline, she is the fabled subject of a mythical forest, but when Mario is attacked by Wario in her domain, she takes it upon herself to guide him to safety.

Mario & Wario
In the game Mario & Wario, the player controls Wanda using the Super Famicom Mouse, providing a safe pathway for the aimlessly-wandering Princess Peach, Mario, and Yoshi, who have had buckets and other objects dropped on their heads by Wario and were all separated from Luigi. Her role is to create safer pathways by utilizing her magic wand to alter the surroundings of the environments and obstacles that were in the way of the blinded heroes. If she was not able to clear the obstacles in front of the blinded characters, the level would not be able to be completed as the blinded characters would not be able to reach their target destination. During the bonus minigames after every ten courses, she uses a hammer to hit Wario's plane for coins. In the ending, Wanda would be seen presenting the "THANK YOU" message on the screen as the heroes defeat Wario and celebrate her success.

Super Mario-Kun
Wanda appears briefly in volume 9 of the Japanese-exclusive manga series Super Mario-Kun. Bowser, however, crushes her, and they fuse together for the rest of the Mario & Wario arc.

Wanda makes a notable appearance in the eleventh volume. The portion that she appears in is based on the story from Wario's Woods. Additionally, her role mimics that of the Sprite from that game. In this issue, Wanda arrives to Peach's Castle Garden and searches for help in order to support her as she tries to stop Wario and his plans. Eventually, Wanda finds the heroes Mario, Luigi, Toad, and Yoshi throughout her search and the four agree to help her on her quest to stopping Wario.

Super Smash Bros. Melee
While Wanda herself does not appear in Super Smash Bros. Melee, the description for the Bucket trophy mentions her role in Mario & Wario.

Super Smash Bros. Ultimate
Wanda appears in Super Smash Bros. Ultimate as a Novice-class support spirit. She is categorized as a Super Mario series character, although her debut game, Mario & Wario, is not part of this series. The spirit boosts the user's magic-based attacks. In its battle, the player has to defeat a tiny Palutena, who is accompanied by Mario, Peach and Yoshi.

The core extracted from Wanda's spirit can be combined with Princess Shokora's core to summon the Sprixie Princesses' spirit, or with Smeargle's core to summon Elline's spirit.

Trivia

 * In preview material for the canceled international release, Wanda was nicknamed "Barrio".