Kang Johnson is one of the two secondary antagonists (alongside Kodos) of the series. He is a Rigellian from Rigel 7. He and his sister Kodos are continuously try to take over Earth and are usually seen attacking Springfield. He usually appears in Treehouse of Horrors but either him or Kodos have been seen in other episodes such as "The Springfield Files" and "Gump Roast" Kang and Kodos have a lot of space weaponry at hand and have their own spaceship. They speak the Rigellian language, which, by coincidence, is identical to English. Although they look identical, Kang has a deeper voice than Kodos. He is the featured character on the on the Season 14 DVD/Blu-ray box set as well as the iTunes cover.
Either Kang or Kodos was seen in the FBI lineup in "The Springfield Files" with other aliens.
Kang once impersonated Bob Dole in order to become President of the United States, in Treehouse of Horror VII's Citizen Kang/Mr. Kang goes to Washington. When Kang was revealed to be an alien, he was still more popular than a third party .
In Treehouse of Horror IX's "Star-ship Poopers," it is revealed that Kang is Maggie's biological father after probing Marge with an insemination ray for a cross-breeding program, which resulted in Maggie growing alien legs and an alien tooth.
The Simpsons Game
Kang (along with Kodos) appears at the end of Mob Rules, when they cause Dolphins to attack humans, cause Lard Lad to assault the industrial zone of Springfield, and invade the mall. However, when they were thwarted, they decided to start attacking Springfield. This causes the Simpson family to enter the game engine to find the creator, but Groening wasn't enough to defeat the aliens because he didn't want to. Soon after God is defeated, God decides to replenish Springfield, returning peace to the city.
- Kang and Kodos are the only characters outside of the Simpson family to have appeared in every Treehouse of Horror Halloween specials.