Yoshi (sometimes specified as Green Yoshi) is one of the Characters of the Mushroom World and an ally of
Yoshi!
Mario and Luigi.He is Mario's best friend. He is a member of the Yoshi species and has aided his brethren in saving their homeland on multiple occasions. Yoshi has also saved other kingdoms from the villain Bowser as well. In his youth, Yoshi
Mario on Yoshi in Super Mario World
managed to rescue and protect Baby Mario and Baby Luigi from the wrath of Kamek and the Koopa Troopa. According to Super Mario RPG: Legend of the Seven Stars, Yoshi is the only one of his species who can speak the language of the other characters. However, in later games, he doesn't speak the language (as shown in Mario Superstar Baseball and Mario Super Sluggers). This is contradicted once again, in Super Mario Galaxy 2, when Yoshi speaks in perfect English. Yoshi made his very first appearance, game-wise, in the Super Mario World level, Yoshi's Island 2. The roles he plays in the series varies from game to game.
Yoshi has appeared playable in every single Mario Party that was released. In Mario Party, he had his own board called Yoshi's Tropical Island. In Mario Party 2 and 3, Yoshi's favorite item was a warp block. If Yoshi was set on as a computer, he would be more than likely to buy a warp block over any other item. In Mario Party 4, Yoshi's favorite thing was the Warp Space, which does something similar to the Warp Block. Also in Mario Party 3, Yoshi's star stamp was Kindness.
In Mario Party 4 (the first installment in the Mario Party series which has a Team Mode), Yoshi's default partner was Donkey Kong. In Mario Party 5, his default partner is Toad. In Mario Party 6, he didn't have a default partner. (Yoshi --in Mario Party 6-- is the only character who doesn't have a default partner. However, before Toadette is unlocked, Yoshi and Toad are considered default partners.) In Mario Party 7, he was partners with Birdo. (However Birdo --along with Dry Bones-- are unlockable characters. So before they --Birdo and Dry Bones-- are unlocked, Yoshi and Boo are considered default partners. But they share different special orbs). In said game (Mario Party 7), Yoshi's Special Orb was the Egg Orb. In Mario Party 8 his default partner is again Birdo (like in the previous installment). (However, Birdo and Dry Bones are both starter characters in Mario Party 8. So Yoshi is default partners with Birdo, while Boo is default partners with Dry Bones.) And in Mario Party DS, Yoshi's default partner is Toad (like in Mario Party 5).