Kerwan

Kerwan was a bustling planet in the Solana Galaxy, and was home to the gigantic city of Metropolis.

Ratchet & Clank
In Ratchet & Clank (2002 game), Ratchet and Clank acquired an Infobot on planet Novalis that featured Qwark advertising Big Al's Roboshack. They tried to find the hero in green by seeking out Big Al and Captain Qwark's personal fitness-trainer Helga, but ultimately only left the planet with a newly fitted Heli-Pack, a Swingshot, and an Infobot to planet Eudora.

Ratchet & Clank: Up Your Arsenal
In Ratchet & Clank: Up Your Arsenal, Ratchet and Clank witness Nefarious' first use of the Biobliterator, turning all of his Tyhrranoid troops into Robonoids.

It's also on Ratchet's arrival on Kerwan that he realized that the "Clank" he'd been carrying around since he'd left Holostar Studios was an impostor named Klunk. After the revelation, Ratchet defeats Giant Klunk and frees Clank.

After the reunion, Ratchet and Clank are called in to fight with the Galactic Rangers in Operation: URBAN STORM. The battle ended in victory for the Rangers thanks to Ratchet's help.

By the time of Ratchet: Deadlocked, Sasha Phyronix had become the new Mayor of Metropolis.

Ratchet & Clank Future: Tools of Destruction
In Ratchet & Clank Future: Tools of Destruction, the duo had to fight off Emperor Percival Tachyon's deadly space armada. According to IRIS Tachyon and his army had left Kerwan after combing Metropolis for the Lombax Secret and the city was under reconstruction. Although this was the same Metropolis from the first and third game it looked completely different in Tools of Destruction mainly because of high definition. This made the city look much more realistic, and alive with sky traffic everywhere, Ratchet also explored a part of the gigantic city never before seen, and this new area had railway tracks that were not seen before either and had Ratchet grinding on them and dodging speeding Mag Trains.

Ratchet & Clank comic series
In Ratchet &amp; Clank: Issue 3: Lost and Spaced, Kerwan is mentioned as one of the planets that were stolen by Artemis Zogg and taken to his galaxy. It is assumed that it was returned to its previous location along with all the other planets when Zogg was defeated.

Changes in appearance
Although Kerwan was the same planet in all three of its appearances, it had undergone possibly the most drastic terrain changes ever seen in the Ratchet & Clank series. During Ratchet's first visit, Kerwan strongly resembled Coruscant from Star Wars, with a surface that took on the appearance of a worldwide city. When Ratchet later returned, Kerwan was depicted as a lush, vegetated world covered in vast oceans. As the duo took off for Polaris it looked like a red deserty world even though Kerwan was not a desert world. However, this could have been a result of Tachyon's attack on the planet. In a commercial later viewed, Kerwan looked lush and vegetated again.

Ratchet & Clank

 * Big Al
 * Helga
 * Qwark Bot

Ratchet & Clank: Up Your Arsenal

 * Nefarious
 * Lawrence
 * Klunk
 * Galactic Rangers

Ratchet: Deadlocked

 * The Brown Ranger
 * Quaternion X
 * Captain Starshield
 * Sasha Phyronix

Tools of Destruction

 * Emperor Percival Tachyon

Ratchet & Clank

 * Blarg Commanders
 * Robodogs
 * Mine Layers
 * Blarg Helicopter Commander
 * Blarg Generators

Ratchet & Clank: Up Your Arsenal

 * One-Eyed Tyhrranoid v2s
 * One-Eyed Robonoids
 * Three-Eyed Tyhrranoid v2s
 * Three-Eyed Robonoids
 * Tyhrranoid Commanders
 * Robonoid Commanders
 * Tank Bots
 * Ultra Mecha-Tyhrranoid
 * Vulcan Turrets
 * Insectoids

Bosses

 * Giant Klunk
 * Insectoid Swarms
 * Nefarious

Ratchet & Clank Future: Tools of Destruction

 * Drophyd Sentry
 * Drophyd Trooper
 * Tesladrone
 * Tachyon Gunship
 * Tachyon Warship
 * Tachyon Walker

Ratchet & Clank: Full Frontal Assault

 * Turret Grungoid
 * Grungarian Demolitionist

Trivia

 * Kerwan makes the most playable appearances of any planet in the Ratchet and Clank games.
 * If one takes a close look, the landmass in the western hemisphere resembles real-life North and South Americas.
 * Apparently, the Ratchet & Clank (2002 game) instruction manual mentions there is a pet shop on Kerwan (possibly in Metropolis), and it specializes in the Hatcher Lizard.
 * While riding on the Grind-Rails in Ratchet & Clank Future: Tools of Destruction, a silver model of the planet is shown, probably representing the Planetary Defense Center. It shows the continents, and where they were placed, of Kerwan.
 * In Ratchet & Clank: Up Your Arsenal, it looked like Todano, except with mirrored continents, just like Aridia and Rilgar are mirrored versions of the previous game's planets.
 * At the back of the box for Ratchet & Clank, there was a Wanted Poster. It had a Last Seen category, and said "Planet Metropolis" rather than planet Kerwan.
 * In Ratchet & Clank: Going Commando, Megapolis served as a stand-in of sorts for Metropolis, sporting a similar theme and background music.
 * Kerwan has a huge city along with Endako and Igliak.
 * Planet Kerwan was originally going to be named Planet Caldera as in one demo of Ratchet and Clank it says Metropolis, Planet Caldera.
 * Kerwan is the only planet from the PlayStation 2 games which reappeared as a playable level in the PlayStation 3 title Tools of Destruction.
 * Kerwan has been invaded four times in the series. Once by Doctor Nefarious, once by Drek, again by Doctor Nefarious and once by Emperor Tachyon.

Behind the scenes
Kerwan was the first level of Ratchet & Clank that Insomniac Games presented to Sony to showcase the game, in which buildings were merely cardboard cutouts of their final appearance, and Ratchet had a Pyrocitor and a Suck Cannon. Vegetation and flying cars were added to the city to make it feel alive.

Appearances

 * Ratchet & Clank (2002 game)
 * Ratchet & Clank: Up Your Arsenal
 * Ratchet: Deadlocked
 * Ratchet & Clank Future: Tools of Destruction
 * Ratchet & Clank Future: A Crack in Time
 * Ratchet & Clank: Issue 3: Lost and Spaced
 * Ratchet & Clank (2016 game)
 * Ratchet & Clank (2016 movie)


 * Non-canon
 * Ratchet & Clank: Full Frontal Assault 𝜇