What is Grandpa William Shortpaws affiliation with the Stiltons?

Grandpa William Shortpaws is a character from the children's book series "The Stilton Family" by Geronimo Stilton. He is the grandfather of Geronimo and his siblings, known for his adventurous spirit and wisdom. His affiliation with the Stiltons is as a beloved family member who often shares stories and experiences that enrich their lives. Through his character, readers learn about the importance of family ties and the value of adventure.