(Bloody Stars, Book 1) In the moorland of WindClan, a kit is found. The kit is taken into the Clan and given the name of Yellowkit. But the rogue blood in her veins is strong, and she can't find any proof that StarClan exists. So when the medicine cats have a vision from StarClan, Yellowpaw can't find that reasonable, and pays the ultimate price for it.

(Bloody Stars, Book 2) After Fallowpaw's death, Logheart has been filled with hate and rage, so much so he has failed to make friends and has become a shell of his old self. So when he is sent on a quest with cats he loathes, he can see no reason in trying- despite the fact that this journey might not just fulfill something physical.