Ninja Bots were reoccurring enemies in Up Your Arsenal. They were encountered on several planets and locations under siege by Nefarious. The Ninja Robots carried a Double-Bladed Laser Sword as their primary weapon. Ninja robots were very acrobatic and were often seen performing back flips and spinning on their staffs. On some instances, such as at the Zeldrin Starport, the Ninja Bots used Shurikens, or Ninja Stars, attacking Ratchet from a safer distance.
They also appeared in Annihilation Nation, being one of the two enemies along with the tank bot to never change color scheme.
Ninja Bot v2 was an improved variant of the Ninja Bot, this variant of the Ninja Bot sported a black coloration.
In Up Your Arsenal, Ninja Bot v2 could also be played through a mini-game in a Qwark Vid-Comic on the VG-9000 game system after entering a code that could be found at the Insomniac Museum. This mini game put the Ninja robot against the Captain Blackstar found in the first Vid-comic. A Ninja Bot v2 was also one of the four playable characters in the Bombs Away min-game.
Behind the scenes
The ninjas were originally far more agile and able do wall runs, dodge player's attacks with back flips and wall jumps, but they were toned down drastically during the pre-production phase because they deviated too much from the traditional Ratchet & Clank enemy gameplay. 
- Ratchet & Clank: Up Your Arsenal (first appearance)