#1 Coldstar is a sort of reverse color-point: black for the body, and the etremities fading to bluish-light grey. He has icy, light blue eyes and, dense, medium-short fur.
#2 Coldstar has no reference or drawing for a reason, if an abstract one. Coldstar has no appearance because Coldstar has no self. You see, in life and death, he refused to be a person. He's never mad, or happy, sad, or nervous, or conident. He doesn't express love or hate. He eats rotting crowfood and fresh, juicy mouse the same. He never acts interest, never acts bored. The only indication of any personhood was his decisions. He is more leader than person: a featureless wind, blowing the clan this way and that. And how are passionate with someone who lacks passion? Shadestripe dug the deepest, pried the hardest. After all, she he agreed to be her mate, but why? Was it love, some plan, the desire of another? She needed something: affirmation, rejection, indifference, anything! Time marched on, and never got anything. Then came his final day. He was weaker than ever been, even more than he'd almost died as a kit. All morning, she begged him to give something, a sign of acknowledgement. After a particularly long, arduous plea, she turned and saw he was looking at her, the slightest spark of frustation in his eyes. Then he died. She mulled it over in her head, pondering its meaning. What had caused it? Her anguish, his dying, the pain, the sense of losing control? She'll never truly know.
(P.S. Coldstar does sort of have an appearance, for if I ever were to draw him, flashback or in Starclan. He's a featureless black silouette of a cat, the image of a "perfect" Moonclan leader.)