Leon the Yoshi is a member of Team Shadow. He was a major antagonist in Season 8, but became a protagonist in the following seasons. Leon is unique as he is the only Yoshi that was not born on Yoshi's Island. Leon ran the training facility in Pandemonium prior to Gigadark Bowser's invasion. After Venus is killed by Gigadark Bowser, Leon decides to go with the Heroes of Legend in order to avenge his friend. Leon reappears in Season 21, where he takes the Heroes of Legend to Venus. When Yami Bakura and Uka Uka show up, Leon witnesses Venus use her Ascent Mode, and reveals he also has an Ascent Mode. In Season 29, Leon is infected during the second invasion of Pandemonium, and is later seen alongside the other zombies on Earth. As of the end of The Grand Finale, Leon is travelling with Venus and Kakashi Hatake, who Leon previously bit, as they search for more food. Leon is later killed in Season 30 by the heroes, whose bodies were being controlled by the Nomadic Mechtogan.
Leon looks almost exactly like Yoshi, but is black instead of green. In Ascent Mode, Leon becomes blue in color.
Leon is determined to prove himself as a fighter. However, he appears to lack the ability to dodge a Falcon Punch as he always gets hit by it even though he could jump over it.
- A running gag for Leon is that he can't seem to dodge a Falcon Punch even though he is quite capable of doing so. Leon managed to dodge a Falcon Punch at last during Gigadark Bowser's siege, but got hit by a regular punch in midair.
- Despite being a Yoshi, Leon is of Pandemonian descent.
- Leon appears to have become Venus' advisor since she became the ruler of Pandemonium, making him similar to Toadsworth and Polari.
- Leon and Venus are the only members of Team Shadow with an Ascent Mode. Coincidentally, they are the only Pandemonians to be zombified.
- Leon is revealed to be Venus' younger brother in Season 29.