Premise: Trumpkin is a fictional character in C. S. Lewis' fantasy novel series "The Chronicles of Narnia". Trumpkin is an intensely practical and skeptical dwarf who lives during the reigns of King Miraz and King Caspian X. He is a major character in "Prince Caspian", briefly mentioned in "The Voyage of the Dawn Treader", and is a minor character in "The Silver Chair".
Hypothesis: Trumpkin  appears in all of the chronicles of narnia books