Final answer:
In the graphic novel 'Amulet,' the late maternal grandfather of Emily and Navin and the past keeper of Emily's stone is Grandpa Silas. He plays a crucial role in passing on the responsibility of the amulet to his granddaughter.
Step-by-step explanation:
Emily and Navin's late maternal grandfather in Amulet, and the past keeper of Emily's stone, is Grandpa Silas. In the graphic novel series, Grandpa Silas is depicted as a powerful figure who previously protected the amulet before passing on the responsibility to his granddaughter, Emily. This series, created by Kazu Kibuishi, explores the adventures of Emily and her brother Navin as they navigate through a magical world filled with challenges and evil forces, all while trying to protect the amulet that was once guarded by their grandfather.