Regulon Four

Regulon Four, or Regulon IV, is a planet in the Regulon star system. It is home to fearsome creatures known as Regulon metalmongers.

The Transformers cartoon
Kup and his platoon were once stranded on Regulon Four and beset by metalmongers.

Wings Universe
The Star Seekers raided Regulon IV's espirion fields.

Descent into Evil
The Autobots Chromia and Flareup defeated the Insecticon Buzzclaw there.

The AllSpark Almanac
Regulon IV was a robotic planet in the Autobot Commonwealth.

Prime cartoon
In an attempt to escape Earth from Unicron's wrath (and to take command of the Decepticons), Airachnid ordered the Nemesis to be taken to Regulon Four. Soundwave, however, forcefully objected to deserting Megatron and they remained on Earth.