Omni was a young phantom at first, concerned with nothing more than exploring the land and getting up to as much mischief as humanly possible.
Originally a more seemingly peaceful creature, he lay low during the majority of his time, only truly becoming involved with others during the first emergence of the Soul Vein, as a quick opportunity to gain power. This quickly changed when on a routine resource collection in The End, his elytra failed, plummeting him into the End Void. This broke his already fragile body, killing him, and imbued him with the destructive power that it held, transforming him into an altogether larger and more powerful being, a wraith.
Months later, after wandering the End in a blind rage brought about by this transformation, he gradually gained control over himself, and eventually left the dimension.
After gaining more knowledge about how the forces of the world worked, he began gaining an interest in the Gods, perhaps in a bid to twist their power to his own. As a dark creature, his natural inclination was towards the night, and the pitch darkness that it brought. This led to the creation of The Unsleeping City, a group of those who thrive in the darkness, as a ruse to capture and control the Goddess of Light, Gwen, and with the assistance of his partners at The Horde, attempt to bring about an Eternal Night.
https://www.youtube.com/watch?v=-nlnnxFjypQ
While successful at first, it was eventually foiled by the resurrection of a Balance god, and after interrupting the ritual, his first life was taken from him.
Soon after the Eternal Night concluded, he was offered a position at The Horde, as the new Horseman of Death, alongside the newly crowned Emperor Tarterus to conquer the many factions within the lands and create a powerful, Imperial Horde.
This endeavour was successful at first, with the conquering of Hopestone and the Enderian Outpost. However, The Imperial Horde made a crucial mistake when attempting to take over the Cafe, wildly underestimating the support that it would have behind it as the server's favourite meeting spot. The Horde forces were swiftly crushed, marking the downfall of The Imperial Horde.
During an attempted assassination of Emperor Tarterus, the Horsemen attempted to fight off the attackers, but failed. During this battle, Omni's second canon life was taken by Krispy.
As people began dropping out of the Horde, Omni attempted to stay as long as possible, cajoling what resources he had left, but it was in vain, eventually coming to the realisation that Tarterus had used and manipulated him through the promise of power, and had in fact, failed him. This led to his disillusionment with his former Emperor, and resulted in his betrayal to the other side, forming a temporary pact with Krispy to support his efforts to bring down the tyrant in the Unremembered Tower event. During this event he stole Tarterus's mask, to make sure that there would be no chance of him ever returning.
During the calamity, Omni stowed away, attempting to stay as far from the destruction as possible, living in a small cabin in a forest. Once this ended, he emerged a few years later, to find a ravaged land. With the other survivors, he helped rebuild, eventually having a hand in the construction of Nightingale City, where he currently resides in a tea shop, known as PolTeageist.
(Pictured above, left to right: RBG, Omni, Tarterus, Comet and King; The Four Horseman of the Imperial Horde with the Emperor)