First "Guess the Cat" Poem!

Life was fine,
Until she left,
To save the Clans,
From distress,
She could feel it,
But I was worthless,
I wanted to prove,
But ended up realizing,
The dark is better left alone,
So I helped,
But was struck by regret,
When the killer,
Became the killed,
By the "hawk",
And the two left were alone,
With the other gone,
It was all my fault.

Who's the cat in the poem?