Gollum wasn't the only thing following the fellowship when they left Moria. They had been followed since they left Rivendell.
The Gods had sent a liaison to the council of Elrond, one who had stayed hidden in the shadows while the rest talked. One, who could follow silently and be trusted to not say a word to those who would go on the quest. One, who could never been seen as the same thing twice. They sent the Assassin.
I stayed hidden in the shadows as the council of Elrond commenced. It was the order of the Gods, Do not reveal yourself to them. Only Elrond knew I was there. I intend to keep it that way. I watched as people volunteered to help the Halfling take the ring to Mordor. Two men, one Elf, one Dwarf, and a Wizard. Another Halfling rushed out behind a bush to plead his case to go with them. When he was given the okay to go, a rustle came from behind me and I transformed just before they caught sight of me. They rushed past and started to complain about not being able to go, Elrond glanced in my general direction. I changed back to my preferred form and nodded. "So be it". Elrond said. "You shall be; The Fellowship of the Ring". They stood there looking all majestic then one of the Halflings said "Great! So, where' we going?
Late that night, I snuck into the Hall of Fire to have a word with Elrond. But first a quick word about me.
My name is Asan Bucklinger. I am 19, sort of. (We'll get to that later) I am a Half-Blood. I am Half Mortal, Half Greek God. My Father is Morpheus, God of dreams. I am his Shadow. Morpheus Shadow is when he gives part of his soul to his oldest Demi-God child. It appears as a sky-blue stone set into our collar bone and houses 1/4th of his power. If Morpheus ever got really killed, The Shadow would leave it carrier and pass to him, bringing him back to almost new. Depending on how long a child has carried it, we could die from not having immortality. It isn't really immortality, we can still be killed in battle, but we never age. Untill we lose the Shadow. Then we age REALLY fast. All our years of life come rushing back to us and we die a horrible death. I have carried it for 2,564 years, that makes me 2,583. I do look good, for an older person. All the carriers share the looks of our father, White, shimmery hair, colorless eyes, that have small bands of color weaving thru them. Our gaze can kill, if we want it to. But we can always read people's minds. A smart person feels it right away, but someone who is a little out of it won't even know it is happening. Having so much power has its drawbacks though, every carrier has to give up something in exchange for the benefits the Shadow brings. The first carrier, Gideon, had wings, and was a great warrior. People called him the Avenging Angel. But he couldn't read, He was killed by a group of rebels who sent him a note through a traitor in the system. The Second one was Sebastian, Who was given the gift of infinite knowledge, but couldn't hear. He was killed when the Trojan War broke out and he didn't hear the soldier come up behind him. The third is me. The Gods Killer, the Assassin. I can shape shift, and am one of the few who can actually kill a god, titan, monster, anything deemed 'un-killable'. But I can't talk, I can't cry for help when I am trapped, I can't divulge secrets unless I transmit them into your mind. That is why the gods made me their assassin.
Back to the actually story. Elrond approached me as I entered the hall. "Follow them as close as you can. Take any form you deem necessary. Engage people only when you have to. Reveal yourself to them only when there is no other option. They leave tomorrow. Good Luck".