His presidency shook House society to its core, led to the formation of groups like the interventionists and Faction Paradox, and set precedent for the creation of unimaginably violent and dangerous weapons for the War in Heaven. (PROSE: The Book of the War)
The Imperator was one of four renegades of his generation, caused by mutations in the breeding-engines. (PROSE: The Book of the War) As a child, he was friends with Thessalia, who was also a member of his house. (PROSE: The Return of the King)
His ambition and personality, which sharply contrasted with the sedate and conservative traditions of the Great Houses, led him to become head of the Presidency on the Homeworld. His career was the first in millennia to dramatically alter Houses' relations with the wider universe. He demanded that their Protocols be forgotten and history itself be redrawn to better suit the Houses' needs and interests.
While based on the Homeworld, the Imperator gathered members of the lesser species around him, encouraging them to regard him personally as a god. Though he made extravagant promises to his followers, he did not go so far as to bring them into his bloodline. (PROSE: The Book of the War)
The Imperator created the Order of the Weal for Thessalia to lead. She said he fancied the title War King. (PROSE: The Return of the King) However, the Order eventually denounced him among the ruling Houses. This provoked the Imperator to abandon the Homeworld; with his followers and mercenaries, he attacked hundreds of cultures in the outside universe in the name of the greater good.
The Homeworld's stagnant society struggled to understand these inconceivable events. After a prolonged period of paralysis, the ruling Houses captured the Imperator, put him on trial, and publicly executed him. This was the first deliberate killing of a member of the Great Houses since their society's foundation. (PROSE: The Book of the War) The trial's result inspired such great regret in Thessalia that she committed suicide in one incarnation, and she obsessively talked about the Imperator and the upcoming War to Larissa toward the end of her life. (PROSE: Newtons Sleep)
The long-term cultural changes brought about in the aftermath of the Imperator Presidency included the increased influence of intervention groups and the founding of House Paradox. (PROSE: The Book of the War)