Also formerly known as Procel as designated by the scientist Wellard Rauss, Tempanimus lay Soulstorm is the name given by Voltaire to the Demon of Riene initially merely as a shorthand descriptive term. The name stuck when Voltaire began to behave as though he were communicating with the creature.
Soulstorm's awakened consciousness began to draw all manner of creature plagued by Soul Corruption. A small cult aspiring to utilize Soulstorm's power managed to acquire a portion by cooperating with Voltaire, creating a second Soulstorm which had to be sealed within the Tartarus Gate at Phantom Deep. Meanwhile, Voltaire had corrupted himself and managed to use magic to channel Soulstorm's power through himself. He was defeated in greater part by Aer Soroval but the final blow was delivered by a stranger with a spear.
When Lunaria's king, Dominic, demanded a tower for his kingdom to rival Solaris' Pillar of Light, the Geniuses initial installation failed to produce the light it was built to provide. Urged by Aeon Digeros, Dominic sent a band of mercenaries escorting the archaeologist Mathias to investigate the odd readings emanating from beyond the Wastelands. Mathias returned to the Unending Road with news of a massive sphere with what he sensed was something alive within. He confirmed it was the cause of the supernatural darkness that plagued Lunaria. On Dominic's orders, Aeon had the creature relocated to the tower. Unable to discern how the darkness emanates from within it, Aeon began to experiment upon it, sampling its essence for use in combination with Anvarian wildlife. Eventually, his contact with the Demon left him affected with what would later be known as Soul Corruption, driving him insane. After Aeon's death, his brainwashed servant, Cipher Janus, took over his work, taking the moniker Voltaire. Voltaire took a serious interest in the creature, going so far as to name it after the "storm it so stirred within [his] soul" and thereafter engage in longwinded conversations with the practically lifeless being. He used Soulstorm to genetically alter several abductees before sending them out into the world. The results earned him a place in Dominic's employ and his experiment was used to enhance a large force of Lunarian soldiers. Despite all of this, the creature remained unresponsive and, in fact, seemingly unconscious.
Later, during the Eighty-Minute War, Soulstorm was somehow freed of his bondage and appeared on the battlefield. Though his impact was removed from memory of all who participated, his own injury could not be forgotten. He disappeared seemingly without trace.
Soulstorm acts mostly unconsciously throughout the story, driven by an urge to reconstitute his physical form.
Soulstorm was created to act as the leader of the Shadows/Hollow, originally called Darklorn, creatures based on the Heartless from Kingdom Hearts. He is a singular entity that would represent all of the Heartless as if they had a singular consciousness.
The Soulstorm Eidols are out-of-body personas created over the years if mostly through genetic tampering. All Eidols possess yellow eyes.