Grandpa -- a.k.a "Hologramps" - is the sensei of the Supah Ninjas and Mike's grandfather. A hologram carrying the family ninja legacy, he guides the Supah Ninjas and trains them in an underground high-tech dojo. He acts as the spiritual leader of the team, and is the heart of this group.
Hologramps is played by actor and author, George Takei. He is best known for his character - Hikaru Sulu, helmsman of the USS Enterprise in the original Star Trek series. He has appeared in over 40 feature films and countless TV guest-starring roles to date.