Sebastian was born... well, he can't remember when, nor where on the map he lived his formative years. His origins are strictly the past for him, and he doesn't dwell on it very much. He doesn't even make educated guesses as to how old he is. What little he will tell is that he was raised in a temple dedicated to the Lady of the Land, a goddess of borders between wilderness and civilisation.
He doesn't remember his parents, but also doesn't really think much about it -- at least he wouldn't admit to. The story is the same told in many, many songs of love between elves and humans. For one reason or another neither parent would want sole responsibility for raising a child of mixed blood.
No matter how content he might have been, times changed and as the temple's flock dwindled, Sebastian was introduced to cities at the tender age of eight. Step by step he fell in with local thieves, only to have a dramatic falling-out with them once he reached his late twenties. From then on he slowly built a reputation that spread through boundaries and continents as time passed, becoming a bogeyman for the rich, some of whom are keen enough to realise (retrospectively) that the folk stories of a Fox have some truth to them.
Recently, he has found romance. Again.
Around 1.75 - 1.8 metres tall (5'9" to 5'11"), athletic. Scarring here and there, most obvious on his hands which he usually covers with fingerless gloves.
Hair is silver, lenght varies; usually at least to his shoulders due to his tendency to get sunburn easily and the need to cover his pointy ears.
Face: angular, occasional stubble. Chin sharp, nose thin and sharp. Bright green eyes, likely to gleam in dimmed or dark places (nightvision, yes). Skin: very pale. Does not tan properly.
A wide-brimmed hat (or any kind of hat that shelters from sunshine) is usually among his personal effects.