Yonder was born on Yoshi's Island. As a child, he loved to go exploring the island and all its environments. It was while exploring the island that he found the legendary and rare Mystic Fruit, which is said to grow every 100 years and lasts only a few days. When he ate it, it gave him the power to gain unique abilities by touching certain items or enemies with his tounge, similar to Kirby. When he got older, he moved to Toad Town, as he wanted to experience more of the world and felt he couldn't on the remote island. He now uses his abilities to aid the Mushroom Kingdom in times of need or when others are in danger.
Yonder is a kind and free spirited soul, who enjoys adventuring and helping out anyone who needs it. He has a strong sense of justice and always tries to make things right. He can be a bit naive at times and has a bit of a temper, but these traits do not show often. Being a brave Yoshi, Yonder would willingly face danger to help anyone in need. He may be brave, but he does have his fears. He seems to be afraid of ghosts, since he becomes uneasy whenever there's a boo or any apparition around. While he loves adventuring and giving his all, he also enjoys relaxing just as much. Yonder is also, like most yoshis, very friendly and always tries to be cheerful, even when things may look glum.
As stated above, Yonder has the ability to gain special powers by touching items or enemies with his tounge. These abilities range from being able to generate and control fire to being able to levitate objects at will. He can keep these powers for as long as needed, but can discard them at any time. His ability may not always work, as some enemies are either to powerful for Yonder to copy while some may not give him any powers at all.