The Kroolboy is an Ork Battleship with a history of piracy, raiding, and otherwise tormenting Armageddon for many years before the Third Armageddon War. This served the Orks well in the early days of their invasion of Armageddon as, whether accidentally or on purpose, it caused monitor station Mannheim to shrug off the Kroolboy's later raids as simple piracy when in fact it was part of the vanguard for Ghazghkull's incoming Waaagh!. Ultimately, Mannheim's commanders would pay a steep price for their apathy.
As the Waaagh! eventually receded from Armageddon, the Kroolboy went back to its old habits of raiding throughout the Armageddon Sector, as well as becoming involved in a civil war on Monglor.[Needs Citation]