Ratchet's Father was well... Ratchet's father. He looked after the Dimensionator until he was defeated by Mr Cragmite-face, leaving his son, Ratchet behind. It is possible that he was short, but still, it was Tachyon's fault for killing him in the first place so Insomniac Games couldn't state what he looked like, or even his name (unless his name was actually Ratchet's Father). Many replaced this historical event with the Tachyon affair.

His name revealedEdit

In Ratchet & Clank: Fu**, Ratchet's mentor, Crazy Frog, revealed his name was Kaden.

Ratchet & Clank wiki
For those without comedic tastes, the so-called experts at the Ratchet & Clank wiki have an article about Kaden.