Congrats to @MangleTheFox1 for guessing the last cat! It was Bluestar! Here's the next one....

Young sweet heart,
Daughter of lion and frost,
Brother thorn,
Clouded friend,
Apprentice of white,
Scared for swift,
Fought prey-stealers,
Sight is lost,
Pack of kill,
Affectionate cloud,
Face of lost,
Brightest of hearts,
Kits so happy,
Life fulfilled.

Who am I?