Four's Grandfather is only mentioned or seen in flashbacks of Lorien's past. He raised Number Four along with Four's Grandmother and fought against the Mogadorians during the invasion, he ultimately died in battle. Henri remembers him fondly, telling John that he loved to make people laugh and was always making jokes and pranks with his invisibility Legacy. Four's grandparents complimented each other greatly, his grandfather was carefree while his grandmother was more quiet and made sure everything went to plan behind the scenes.