Umbra was once just a nameless and clueless feral Shadow Pokemon before it one day awoke from its feral mind and became cognizant again. With no clue what was going on, the Pokemon could only find somewhere safe to hide away from the other, more feral, Shadow Pokemon.
It was eventually discovered by a group of other 'awoken' Pokemon who took it in and nurtured it - teaching it how to handle living in awareness in such a dangerous world.
It formed a bond, as did most, with the group's leader Genesis or "Gene" as he had come to be known as. Genesis showed it how to hone its psychic and shadow abilities so that it could better defend itself when in need.

Umbra has a very strong psychic ability as a Shadow Pokemon without the need to evolve. It is capable of getting into the minds of others and possessing their bodies as 'vessels' or hypnotizing others. Defensively, the Pokemon may temporarily stun and blind other Pokemon as a means of getting out of trouble.
Unfortunately it became separated from its coven when a hunting party attacked it and Gene, to which Gene made it flee while he held off the attackers.

It is later found by Ellis (https://www.furaffinity.net/view/42865093/) and finds itself under a new name called Umbra. The two form a close bond while they travel together. Umbra primarily on its journey to locate its old coven and see if its friends survived the attack.

Umbra is a male, but uses psychic illusions and possession techniques to bounce around a spectrum of appearances and identities. It is often referred to by it/its and he/him.