From Fallen London Wiki
Duchess is White, (she’s nobility, she evidently cares about order and the proper manner of things) Tatterdemalion is Black, (despite his evident Dawn Machine affiliations, he's still a rather chaotic figure in his interactions with you, and I can easily see his complicated relationship with the Dawn Machine resulting in wanting to destroy both it and the more natural stars) and Shepherd is Red (all he cares about are his friends and getting his sheep moon-miser back, not any higher ideals.)