[1] Ratchet is an anthropomorphic alien creature known as a Lombax, while Clank is an escaped robot (real name: XJ-0461 or Defect B5429671) who soon teams up with him.

Ratchet was intended to be a mascot character for Sony to use to compete against Nintendo's Mario, Sega's Sonic the Hedgehog and Microsoft's Blinx, replacing Crash Bandicoot in the sixth generation of video game consoles (Game Cube, Dreamcast, Xbox and PlayStation 2).

Ratchet was originally envisioned by Insomniac Games Vice President of Programming Brian Hastings as a space-traveling reptile alien who would collect various weapons as he progressed through the game;[2][3] Ratchet's final form was decided upon after Insomniac looked at various terrestrial creatures, such as dogs, rats, and feline features stood out to them because of the sense of agility associated with it.

[4] Clank spawned from an early idea involving a number of small robots attached to Ratchet, which would perform different functions.

"[8] He described David Kaye's performance as Clank as "quite engaging, and in some cases, charming, especially when he finishes a level or gains a weapon.

[17] Johnny Liu of GameRevolution described Ratchet as having a "blue-collar attitude," appreciating that he's not a "typical goody-goody" though criticizing that he wasn't fleshed out.

Perry appreciated that he became "a little more forgiving and a lot more palatable,"[20] while Carlos McElfish of GameZone felt his new voice actor "forc[es] a psychological reset in the minds of players.