The Pit Bulls
The Marik Militias use a color scheme first seen in 2620--purple with red accents on the right side and blue on the left.
Per FM:Free Worlds Legue, page 64.
Each 'Mech displays the Marik Militia crest - a stylized Marik Eagle on a red and blue background - on its left arm or weapons pod. The insignia of the Twentieth shows a snarling pit-bull terrier, a breed of dog renowned for its tenacity and violence. Per FM: Free Worlds League, pages 53 and 64.