What's the noun for mythopoiesis? Here's the word you're looking for.
myth
A traditional story which embodies a belief regarding some fact or phenomenon of experience, and in which often the forces of nature and of the soul are personified; a sacred narrative regarding a god, a hero, the origin of the world or of a people, etc.
(uncountable) Such stories as a genre.
A commonly-held but falsebelief, a common misconception; a fictitious or imaginary person or thing; a popular conception about a real person or event which exaggerates or idealizes reality.
A person or thing held in excessive or quasi-religious awe or admiration based on popular legend
A person or thing existing only in imagination, or whose actual existence is not verifiable.
“But like all religious doctrine there is plenty of mythmaking and mysticism that goes with this.”
“And yes, one has to be vigilant in the way that he suggested and try to spot falsehoods, examples of mythmaking in the stories that people tell about the world.”
“Django, for example, rewrites history not with the brutal nihilism of Peckinpah's westerns but with his own brand of mythmaking.”
“By his silence, and his refusal to mediate between his art and his audience, Greaves collaborates, unintentionally, in his mythification.”
“Is this why you rail against the rampant mythification of Los Angeles, because it conceals so much of the actual living that's done there, the actual history it possesses?”
“There's exaggeration and mythification here, not surprisingly.”
“You might as well forget or throw mythopoesis out of your reckoning of the originality and authority of artistry in Soyinka's poetry and drama.”
“As such, they connect with a wider discourse, inherited from the Romantics but with origins in the ancient world, according to which nature is inextricable from mythopoesis.”
“The effect has been to objectify these occupations and give short shrift to their mythologizers.”
“Victor and Adrian are already defeated, but they function as mythologizers and this is a crucial role in the maintenance of a sustaining sense of Indian identity.”
“The mythologizers of World War II not only have played down the sorry treatment of black troops but also have largely neglected to invite black combatants to the victory party.”