The Krell 'Empire Of The Green Sun' had spread throughout the galaxy for hundreds of years and needed a constant supply of soldier-slaves to fuel its expansion.
The latest discovery of a planet full of the most suitable creatures, promised much.

ScoutKaptain Drec of the heavy scoutship ‘Emperor Buntar IV’ looked at the greenish planet below.
It was mostly covered in water but inhabited by the most ruthless and bloodthirsty, semi-civilised beings they had yet encountered!
He was ecstatic as he envisioned the rewards for finding Earth and the Humans!