Tolkien says the sub-creator may fall by becoming possessive, clinging to the things made as “his own,” wishing to be “the Lord and God of his private creation.”(Letter to Milton Waldman, publisher, 1951)
The story-maker can become a tyrant over the story. The artist can confuse stewardship with ownership. The creature can try to become God over a private world.
This connects directly with ego, false authorship, the Demiurge, the Ring, and the danger of making a world in order to possess it.
Art, Power, and the Corruption of Story
Art versus Power
Tolkien says the corrupted sub-creative desire leads toward Power: making the will more quickly effective, using devices or magic to dominate, bulldoze the real world, or coerce other wills. (Letter to Milton Waldman, publisher, 1951)
The difference between Art and Power. Art reveals, offers, enchants, and participates. Power dominates, accelerates, possesses, and coerces.
The ethics of storytelling: true story enchants; false story manipulates.