"Thank You Son. Thany You for reawakening The Pure Evil, That lay dormant within me for these many years." - Grandfather
Grandfather (voiced by Neil Ross) is the main antagonist of KND Operation Z.E.R.O. He's the father of Father (The Delightful Children from Down The Lane), Nigel Uno's father, along with Numbuh 1's, & The Delightful Children's grandfather. His plan is to rule the world so that they can make bowl after bowl of Tapiyoca pudding just for him. The only one that was able to stop him was Numbuh 0, a long lost operative who became Nigel Uno's Father, the legendary Numbuh 0. He met his end after Numbuh 0, had them both inside the decommisoning chamber, wiping out their memories.
- Grandfather will become Aaron's enemy in the near future.
- Grandfather will become Arik's enemy in the near future as well.