General Description
Hair: Usually a curly/wavy dark blue, at any length from shoulders to knees. He has also occasionally worn it red and short in a typically messy, boyish cut.
Eyes: Red.
Markings/Tattoos: Inverted cross on the back of his neck. He's got assorted scars all over his body, which he sometimes manages to hide.
Others: Gravel still has a child-like body, for he is still young, and was "kept" that way by his father. He's rather scrawny, has boyish hands with long fingers, and more than a few scars. His "official" demon form shows him with pointy ears (and sometimes even with a typical 'devil' tail), however he may or may not show them to the world, depending on where he is, or who is looking. He used to have bat wings, which were ripped off when he was still young.
He's short in height, even for a 15 years old.
Clothing and Accessories: Black or blue jean pants, red shirt. He likes jewelry (gold only, no silver for him), and is often seen wearing a nose ring, several ear piercings, and a lip piercing. He likes leather, jeans, and either very tight or very baggy clothes.
Personality
Dislikes: Sleeping, demons, Heaven, Hell, his real father, angels, his powers used to dislike, he's learning to like), abuse of any kind, studying, learning, reading.
Abilities: Mind powers- he's got telepathy and some empathy, he can read minds, project his own thoughts into someone elses' (provided they're "connected"), trace lines of thought (useful for finding people), see people's dreams and read memories. He can use all this to his advantage to somehow convince weaker minded people to do as he wishes, however, he's only just learning to use most of his powers correctly. he's also got typical superhuman strength, agility, speed, etc, but it's not as great as other demons'.
Weaknesses: His powers, as they are so strong and he is not too used to them still, he is not always in control of them.
General: As a matter of fact, Gravel is quite a good, honest person... deep down. At first glance he is a cocky, nosy, annoying brat who talks back and is generally disrespectful to his elders, except when it's convenient. He's grown quite a bit from the past, where he used to be a loner and far more shy with people, but he still sometimes reacts this way with some people.
At the end of the day, it all comes down to his (frail) state of mind at the time he's being addressed, and how far he's pushed to respond to people. He's not entirely balanced.
Background History
At one point, Gravel had managed to escape Hell's grip for long enough that he thought he had finally found a bit of peace, and even someone to care for him-- but that all ended too quickly as the man that had taken him in disappeared off the face of the earth, heaven and hell, and Gravel could never find him again despite his best efforts.
Gravel tried to get past this and after a few years of most difficult times, trying to learn to use all of his powers and cloak himself from other demons, he finally found a couple that had recently lost their child and; using his powers on them, had himself accepted as their own child. Ever since, Gravel has been living with this family, running away at nights to enjoy what his demon side allows him to enjoy the most, and back every morning to play the part of a human child, a very bratty, lousy student, who is a little unbalanced, but that the parents love and care for.
Gravel leads a fairly happy life now, and tries to forget all about his past before he met this family, as it is all very painful for him.

