Castle of Big Guy the Stilted

Castle of Big Guy the Stilted is the World 4 castle, appearing in Yoshi's Island DS. The boss of the castle is Big Guy the Stilted, a Shy Guy-operated robot. The player plays as Blue Yoshi in the level. Blue Yoshi uses two fire-proof stilts throughout the level that help it cross the lava.

In the background of the castle, it is revealed that this castle is where Shy Guys get all their training (they also train in Yoshi Tower). It appears to be something similar to a school. In the castle, they appear to be taught how to walk with stilts and they are taught about who Yoshi is. It is also here that they grow Piranha Plants. There also appears to be a Drying Room, where the Shy Guys hang their wet clothes and leave them there so they dry. Shy Guys use ladders to travel around the castle, although Yoshi doesn't get to use ladders. After clearing the level, a cut-scene tells of Bowser's plans to take over the world and explains the story of the Star Children.