Theo Heap- is the youngest grandfather of the Heap family on Silas' side and is Silas' uncle. He is one of the characters in the Septimus Heap book series by Angie Sage. Theo is one of first generation of Heap brothers.
He is a shape shifter. When he got old he decide to permanetly shift into a Storm Petrel.
On stormy nights in the Marram Marshes, Zelda keeps a lookout for any Storm Petrels which might be blown away to the marshes and hopes to meet her brother again one day. In Magyk there is an instance when a Storm Petrel comes to sit around Zelda's roof one stormy night and it becomes clear that it is Theo Heap since he sits on the roof of Zelda's Cottage and says to himself that she has always had a talent for seeing the truth in the pond.
Theo is brother to Benjamin Heap, and Zelda Zanuba Heap. His brother married Jenna Crackle and had six son's. His nephews are; Alfred Heap, Hengist Heap, Ernold Heap, Edmond Heap, Silas Heap and Garth Heap and one neice Lois Heap.
He is the Great Uncle of Silas' seven children;
Sam Heap, Nicko Heap, Simon Heap, Jo-Jo Heap, Erik Heap, Edd Heap, and Septimus Heap and adoptive grandfather to Jenna Heap. He has a brother in-law is (Titus Willow) and sister in-law (Thomasine Tremaine).