Exodus Van Zandt was once a peaceful unicorn, living a quiet life in a shack on the outskirts of The Everfree Forest. His career was that of a nameless, faceless, run-of-the-mill independent carpenter/architect. He lived with a formerly homeless mare named Sojourn Myth for an extended period of time, until he helped her build a home so that she could have a permanent residence. Since then, Sojourn worked for Exodus, spreading his name and getting him more work (many of his clients also being homeless) in the area, so that he (and by extension, she) could have a better living.
Mythical Tree of Legend?
One evening, Exodus heard of a legendary tree, deep in The Everfree Forest, that was made of the strongest wood possible in all of Equestria. Exodus reported his findings to Sojourn, and told her of his plans; the very next day, without hesitation, Exodus set out on a quest to find said tree. He knew that, if he found that tree (and possibly others like it), he could make some seriously long-lasting homes that might put his name on the map forever.
On his quest to find the legendary tree, Exodus got hung up on the edge of a chasm; his hoof was caught in a crack on the ledge. He struggled for what seemed like hours to free himself until he finally collapsed. Exhausted, Exodus fell asleep and, sometime in the night, his hoof came loose from the crack. He slid from the cliff, still asleep, and plummeted to the craggy rocks below. He was unable to awaken and gather his faculties...
Exodus awakened an indeterminable time after the incident, but something was... different. He was many miles away from The Everfree Forest, and he was... floating. He soon realized that, not only was his horn destroyed, but he was also no longer alive. But he wasn't sent to an afterlife; instead, he remained in the realm of the living. Was there something more for him to do in Equestria for his life to be complete? What did he have to do to "move on"? Stupefied, he made his way to his former home/workshop. He attempted to pick up his tools with his unicorn magic, to no avail. He attempted to pick them up with his hooves, also to no avail. His career as a carpenter was over. Exodus made his way to Sojourn's home, but she was nowhere to be found. With no other leads or clues, Exodus made his way into Ponyville.
As Exodus traveled about he noticed that not only could he fly, but he could also pass through anything he wanted. This was... fun! The world of flight and ethereal passage was a world he had never been a part of before. In an ironic twist of fate, his untimely death brought about a new zest for life! Exodus became determined to do a variation of new things and lead a different, more interesting life this time around... or at least, until he figured out why he was stuck in the living realm.
Exodus is very approachable and friendly, although some (most?) ponies may be terrified/off-put by his ghastly, haunting visage. He is quite intelligent, but a little old-fashioned. As a ghost, he is a bit of a trickster, and may pop out of somewhere unexpectedly just for a fright. He can usually be found swirling around Ponyville or haunting The Everfree Forest (given that he is invulnerable to creature attack).
Exodus was very close to Sojourn Myth, but she is nowhere to be found. Beyond that, Exodus has no other family in the area. His parents have long lived in Fillydelphia, and he visited them only sparingly before his death.
MiscellaneousExodus has a ghastly speech patten that forces him to drag his 'S'; for example, "Steven Magnet is thrashing about in the sea" would sound like, "Ssteven Magnet iss thrasshing about in the ssea".
Since becoming a ghoul, Exodus can pass through solid objects, is invulnerable to physical attack, and can fly (but not quickly). He also never needs to eat or sleep, but he does require a certain amount of rest, or else he becomes weak. However, he can no longer use unicorn magic, pick things up, or touch anything/anypony. The only way Exodus is able to affect anything physically is if he swirls about fast enough to create a small wind gust, which is just enough to move light objects (leaves, book pages, etc).
When a pony puts any part of their body through Exodus (or when Exodus passes through said pony), the living pony will feel only a cold, light tingling sensation.
Exodus' Cutie Mark used to be a circular sawblade with two hammers beneath it but, when he perished, it warped into a tombstone with a skull and crossbones on it.