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

Fur of grey,
Eyes of blue,
Apprentice sharp,
Warrior new,
Loving true,
Rejected few,
Anger inside,
Hurt from the ride,
Threatened to hurt,
Found secret out,
Killed very sadly,
By one who's named holly.

Who am I?