Ninji

Ninjis are black, star-shaped creatures that first appeared in Super Mario Bros. 2. In this game, Ninjis served Wart, the tyrannical ruler of the dream world known as Subcon. Apparently, Ninjis come from the dreams of NES players. There are two types of Ninji: the first type charges at Mario, suddenly jumping as they approach; the second type remains in one place and jumps up and down. Giant Ninjis also appeared in this adventure, albeit only in its Super Mario Advance interpretation.

Ninjis have had many changes over the years. Their artwork originally depicted them as having fangs and claws on their feet. They shared the same sprite in Super Mario World. Their eyes were also different. However, in Super Mario All-Stars, they were recolored purple and given a goofy expression, with white teeth and more detailed ears. Starting with Paper Mario onwards, they took on a friendlier appearance and do not appear to have claws or fangs. Instead of a visible mouth, they have red cheek-blushes, and their eyes have changed to be more rectangular than two circles. They are primarily black, but some games still show purple on them.

The Super Mario Bros. Super Show
Despite appearing prominently in its opening sequence, Ninjis only appeared once in The Super Mario Bros. Super Show!, in the episode "Karate Koopa", where they aided Karate Koopa in his plan to capture Princess Toadstool and sell her into slavery for a fortune. In reference to their English namesake, they served as skilled martial artists and spoke in thick Japanese accents.

Nintendo Comics System
In Nintendo Comics System, Ninjis only made small appearances, with one appearing in the background of the story "The Legend", while several, having been beaten senseless by a sleepwalking Mario, who believed himself to be Dirk Drain-Head, appear in "Bedtime for Drain-Head".

Super Mario World
Ninjis also appear in Super Mario World. In this game, they serve King Bowser during his rule of Dinosaur Land. They make their appearance in only one level - the final level, in fact. They blend in the darkness and are difficult to see in Bowser's Castle (unless the searchlight is activated). The Mario Mania Player's Guide (1991) describes Ninjis as "Mini-Ninjas," stating that they have been driven insane by their long isolation in Bowser's Castle. It is unknown if these Ninjis are still manifested from dreams like their SMB2 counterparts, or if they are a naturally occurring species in Mario's world. They are one of the few enemies not seen in the credits.

Super Mario World TV Series
In Super Mario World animated series, Ninjis, though brown in color, appeared in the episode "The Yoshi Shuffle" as spectators to Yoshi and Mario's football game against Bully, Big Mouth, Cheatsy and several Koopa Football Players in Neon Castle.

Super Mario Adventures
In Super Mario Adventures, Ninjis, depicted as wielding spears, make several appearances; first appearing in the siege of Princess Toadstool's Castle, Ninjis also appear when Princess Toadstool attempts to escape her confinement in the Koopaling's Tower, aiding Wendy O. Koopa and a brigade of Koopa Troopas in stopping her escape. Later, a Ninji, apparently buying a camera from Friendly Floyd, appears at Bowser's wedding to Princess Toadstool.

Hotel Mario
The Ninjis in Hotel Mario were called Mini-Ninjis, but there is no difference between regular ones and minis, as in Super Mario World. In Paper Mario, the Ninji act as the protectors of the Star Kids in Starborn Valley and are friendly, non-enemy characters. They also come in few different colors: Black and Purple.

Paper Mario Series
Ninji are characters living in Starborn Valley, they are the caretakers of the Star Kids

Mario vs. Donkey Kong
In Mario vs. Donkey Kong, there was a toy version of the Ninji, known as the Mini Ninji.

Mario Party Advance
Mario Party Advance shows Ninji as a huge fan of Toad Force V. Ninji will give the player a Gaddget if the player gives him a DVD of Toad Force V.