辞

Myth is a deity who has the power to rewrite reality by changing the contents of letters she receives from desperate humans. She has amnesia due to falling down a set of stairs.
Myth and Will are actually a pair of robots named WILL created by a pair of married scientists in order to save their late kids from a fatal car crash by rewriting history. They were created with distinct personalities and distinct abilities and were fought over as soon as they were revealed due to their immense power to rewrite reality. The fallout of the fight over WILL ended humanity, with the two robots outliving it by hundreds of millions of years. Myth had been dormant for a long time prior to the events of WILL: A Wonderful World.