Stefano

Stefano is Mario's third brother and a playable character in Super Mario Scralaxy.

Lore
According to the Character Info Block in Peach's Castle, Stefano was lost in space for years. Some time before the events of Super Mario Scralaxy, he was rescued and brought to the Mushroom Kingdom.

Super Mario Scralaxy
In Super Mario Scralaxy, Stefano first appears as an NPC in The Mushroom Festival. When interacted with, he says, "Hey there, bro! Happy Mushroom Festival!"

Stefano is initially locked and must be unlocked by beating Showdown on the Falls.

When playing as Stefano, pressing down makes him dive and his special ability is throwing a fireball.