whooops can I change my answer to Organization 13's Roxas.]

One remaining with eleven dark lights, - this sounds really close to organization 13

Another goes out with every mortal fight. - Dont know

Why just a year ago we were all shining bright, - before they became nobodies they where people.

But the memories can fill you with fright. - Hmm on the tip of my tongue.. cant explain.

Take another step no more,

For we shall guard this sacred door.

Thats all