Shoy

Very reserved and quite. He can be overly sarcastic and sassy when dealing with people he dislikes.
Demon, disguises himself as human while searching for those to make contracts with.
Most contracts are small and Shoy will gain a portion of their life force (basically years off the person's lifeline) in exchange for a quick service or short-term ability.
When a larger contract is completed Shoy gains control over their soul completely and the person's fate for the rest of their life. The ability to change anything in the person's life is what gives Shoy his power.

Shoy serves Charlie under a very large contract. It is unknown on what was discussed.
Somehow in their contract it was agreed Shoy is to serve Charlie as an assistant/butler of sorts until the contract is complete.
He's not very happy about it and will express his feelings to Charlie in the most disrespectful way he can think of, all while carrying out his orders.