Special Equipment:

Gray carries the sword Arimath, a mildly enchanted longsword.

Appearance:

Gray appears to be a tall human woman.  She has long, silvery-blond hair, and dark gray eyes.  She is fairly attractive as well.  She always wears a long, dark coat covered in pockets.  This coat reaches to her ankles, and she will not take it off while there are others present.  Only a very few have seen her without it, and only after they know her secret.  Her coat hides a pair of severly atrophied and useless gray-feathered wings.  The feathers are dingy and generally unhealthy looking, and tend to fall out.

Background:

One of the driving goals of every alchemist is the Elixer of Life, which grants eternal life.  No one is known to have found it.  But one has.  The alchemist discovered what the crucial ingredient was: the so-called “Blood of the Balance.”  This translates to the blood of an archon, a special variant of daemon.  Daemons are the offspring of a demon and an angel, and are very rare.  Archons are the offspring of a fallen angel and a risen demon, and are rarer still.  They are the embodiement of cosmic balance.  The alchemist learned the complicated and thought-to-be impossible ritual necessary to summon an archon.  He got Gray. 
He held her prisoner for several decades (she lost count), drawing off blood whenever he had a use for it, which was often.  This period of imprisonment has damaged Gray, physically, emotionally, and mentally.  Eventually, Gray escaped with the aid of some adventurers who decided to raid the alchemist’s castle.  She took the sword Arimath, which had been a component of the summoning spell with her.  (The spell has affected the sword, and none but an archon may wield it.)  All of this was a few centuries ago.

Gray is ageless, but she either cannot remember or never knew how to escape the mortal realm into the realm of the angels or the realm of the demons.

She has spent the last few hundred years wandering.  She has run into a few demons in those years, and one angel, but the weren’t the sort of meetings that would allow her to ask a favor. 

Gray’s imprisonment has left her with scars all up her arms.  It has also left her wings crippled and useless.  It has also made her intensely afraid of the alchemist, and distrustful of alchemists in general.  Her memory is also impaired, and she cannot remember anything before she was summoned. 

Roleplaying Notes:

Unbeknownst to Gray, the alchemist lives yet.  The ritual that granted him immortality tied his life force to hers; he cannot be killed until Gray dies.  In fact, the only way to kill him is to kill her.  This sympathetic link is only one way: she does not feel his injuries, but he might feel hers.  He is immortal and invulnerable, but when Gray dies, she takes him with her.

Gray has lost all faith in gods, and even in angels and demons.  If she was mortal, she would be an aethiest, but as it is, she simply does not take them seriously.

Being an archon, Gray is afforded some measure of respect by angels and demons, and would generally be granted passage through their realms.

There must always be at least one archon in existance to keep the universe in balance.  As far as Gray knows, she is the only one.