Mercenaries

Periphery Star Guard

Enemies of Entropy

Star Guard units are painted in a flowing coat of black and dark blues to emulate the night sky. White dots represent stars the unit has visited, while kills are represented by larger white dots.

Per Mercenaries Supplemental 2, page 54.

Other references:
Riever, Mercenaries Supplemental 2 (color plates)

Color Scheme
Insignia

Their insignia is a star-filled night sky. Per FM: Mercenaries Supplemental II, page 54.