"Have you ever fought anything as vile as me?"
Umbra Groudon is a Groudon-like entity from another dimension who seeks to conquer the Pokémon universe. It appears as the main antagonist of the Pokémon fan fiction, The Spirit Devourer and its sequel.
Umbra Groudon is an evil entity from another dimension known as the Ravaged Realm. It was born and has been asleep since the beginning of time for the Pokémon universe, but was still fully aware of said universe, and even had dreams about conquering it the instant it awoke.
Umbra Groudon is an evil and destructive being who desires to usurp Arceus and reshape the Pokémon universe to its own liking. To make matters worse, it doesn't even have a sense of honor nor redeeming qualities, and instead has a dark sense of sarcastic humor. It is also very manipulative, allowing it to easily make allies, only to betray them later.
Umbra Groudon can fire a purple laser beam from its mouth that has power almost equal to Arceus' Judgement attack, and it can also project a tractor beam from its eyes that lets it snatch and devour the souls of other creatures for sustenance. Also, because it isn't a real Pokémon, Poké Balls have virtually no effect on it. Umbra Groudon can also teleport between different dimensions at will and has the capacity to march underwater or in lava with the exact same ease as it can on land. Dialga and Palkia's time and space altering effects don't seem to work on Umbra Groudon, and it is capable of mind controlling others to some degree. Its size is comparable to that of a wailord. In terms of its melee capabilities, Umbra Groudon possesses incalculable levels of strength and durability, allowing it to essentially outmatch any opponent at close range combat, while also suffering little to no harm from conventional Pokémon and/or human attacks. It can also communicate with other lifeforms using telepathy.
Umbra Groudon has a deep, masculine voice with a demonic undertone. It also speaks in first person (obviously). Furthermore, like most of the Pokémon anime characters in the English dub, it has an American accent. Also, its non-telepathic vocalizations simply consists of various roars, growls, and snarls.