Grandfather (KND)

"Thank you, son! Thank you for reawakening the pure evil that lay dormant within me for these many years...And now, get out of my sight!!""

- Grandfather

Grandfather was the main antagonist of Operation: Z.E.R.O.. He was a demonic being who ruled the world before he was overthrown by his son, Monty Uno. Many years later, he was revived by his son and successor, Father and began transforming the people of the world into Senior Citi-zombies. Grandfather was very tall and lanky, and significantly taller than a normal person. He had a bald head and a large beard with long, scraggly strands of hair. Despite making only one appearance, Grandfather is by far the most powerful and evil villain in the series.

Grandfather was voiced by Neil Ross who also voices Colonel Volgin from Metal Gear Solid 3.

History
Long ago, Grandfather ruled the world and forced all children to work in his tapioca factories. One day, his son, Monty Uno, discovered the Book of KND, led an uprising of children, defeated his evil father, and erased his powers and memories.

Years later, Grandfather's other son, Benedict Uno, used the Recommissioning Module on Grandfather, then a decrepit old man, to restore his former self, and expected to work together with him to destroy the Kids Next Door and rule the world alongside him. Instead, Grandfather shunned his son, ordered him to leave, called him a failure, and said that he liked his other son more.

He then revealed his plan: To turn all the kids in the world into Senior Citi-Zombies, as well as everyone who was ever a kid. The villains cheered, until they realized that they all used to be children and that this amounted to every person in the world. They tried to flee, but in vain. Grandfather turned all of them into his zombie minions, and ordered them to invade the Kids Next Door's treehouses throughout the world, turn them into zombies as well, and turn the treehouses into tapioca factories. Soon, every nearly KND operative (and presumably every person) on the planet was transformed, save for Numbuh 1, who would re-commission his father, Numbuh 0.

After establishing his rule over the world, Grandfather turned his efforts to finding and destroying the Book of KND, as it could provide children with hope; the only thing that could defeat him. Grandfather arrived near its location just in time to be confronted by his son Monty, who was carrying the book in his back pocket. Monty wrestled with Grandfather until he found the Book of KND. Monty was able to resist Grandfather's power, but soon began to succumb to it.

Monty was able to fight off Grandfather long enough for Sector V to launch the KND Moonbase at him, and seemingly destroyed him. However, Grandfather survived relatively unscathed and emerged from the wreckage, only to find out that he was standing in a Decommissioning Chamber from the Moonbase. Grandfather and Numbuh 0 were both decommissioned once again, and turned back into their harmless, and clueless adult selves.

Powers
Grandfather had the ability to turn people into Senior Citi-zombies; monstrous, geriatric undead who could turn others into zombies as well, through their touch. Although people turned into Senior Citizombies did retain a semblance of their personality, they invariably became the obedient minions of Grandfather and attempted to transform anyone they came into contact with. That power also affected inanimate objects, and made them Victorian Era in appearance.

In addition, Grandfather possessed several other superpowers similar to his son, Father, but are much more advanced. He has powers such as extreme pyrokiness, psionic abilities, shape-shifting, levitation, and superhuman strength & speed. He is also seemingly immortal while he had his powers since not even 39 gazillion tons of red hot metal and duct tape was able to crush him and he may not age or die as well.

Trivia

 * Grandfather was reawakened by using the Recommissioning Module, despite not being a member of the Kids Next Door. This also implied that he was defeated in the past by a Decommissioning Device, despite the KND (7th Age/Futuristic that is) not even existing prior to his defeat. However, it's possible that the Recommissioning Module is able to restore anyone's lost memories, not just people who've been put through Decommissioning.
 * Operation: C.A.K.E.D.F.I.V.E. involved the Annoyingly Cute Triplets Who Lived Upon the Hill, who were enemies of the KND during the nineteenth century. Father referred to the mother of the ACTWLUH as his great grandmother, which would make her Grandfather's Grandmother and one of the triplets his mother. It was shown in Operation: Z.E.R.O., that Numbuh 0 was the founder of the 7th age of the KND and that the 19th century was a totally different age.
 * Grandfather's overall design resembled Aku from Samurai Jack.
 * Grandfather's sons and grandson were among the only characters to never be turned into Senior Citi-zombies.
 * Numbuh 1 and Sector Z were the only people seen to be totally immune to Senior Citi-Zombification, because they were seen touching the zombies and remained normal. That implied that they would be the future heirs to Grandfather's powers, though it was also possible that they needed to be touched by Grandfather himself to undergo the process.