That's a ship from me! It's obvious that Clear Sky cared about her. Even after Star Flower was "kidnapped " by Slash, Clear Sky do as much as he could to save her. You can be thinking : Well, of course, she's his mate, after all... But a heartless cat like One-Eye or Slash will never do that. They wouldn't even try. That's a proof that Clear Sky is not heartless.
Star Flower was the perfect mate for him. She was gentle and caring. Clear Sky finally found someone he could be happy with, at last.