“Let’s just keep embracing each other forever,” says Yu-no, fulfilling her and her father’s repeated promises to never part from each other. Takuya tells Yu-no “your body is so warm,” implying their continued sexual relations. As wondrous music plays, Takuya and Yu-no witness a tree sprout and grow. The tree represents Vrinda’s Tree, the method interdimensional travelers like Koudai use to diagram and conceptualize “history” as a chain of cause-and-effect between different nodes of a tree diagram rather than as a chronicle of forward movement through time.
Nude in the Eden of Yu-no’s childhood and Takuya’s dreams of Kaytia, the incestuous father and daughter couple experience what Eriko calls the “root of events,” that is, the beginning of all universes at which causality began.
But this Adam and Eve (given the tree) are more than passive observers. On the Mitsuki route, Takuya and Ryuuzouji discuss and firmly reject the Big Bang theory as inadequate for the original cause of causality. Yu-no naming Vrinda’s Tree as though the sprout is her child suggests that Takuya, a mock inversion of Uranus, fulfills this conversation by somehow impregnating his daughter with spacetime.
(The Big Bang is Takuya ejaculating.)
In addition to her Oedipal craving for her father, Yu-no, in a perverse reflection, satisfies Takuya’s lust for Kaytia. Yu-no–Takuya is simultaneously deliberate true incest between daughter and father and simulated incest between mother and son. Like Takuya’s mother and like her own, Yu-no is a busty, wide-hipped blonde woman and priestess of the God Emperor who shows Takuya unconditional, fawning devotion. While Ayumi, Kanna, and Sayless fulfill Takuya’s desire for a devoted pet-like sex mother in different ways and to different degrees, these earlier simulations of Kaytia are not quite dependent, devoted, or incestuous enough. That the story of Takuya searching for his “Pops” ends without him finding the old bastard might seem a strange writing decision until one realizes that Takuya, in the culmination of this Oedipal narrative pattern, finds what he has genuinely wanted all along: complete, incestuous safety and isolation from other people, forever embracing the opening wet dream of his mother given physical form as a daughter who lusts for him the same way he did for Kaytia and who promises to never let go, this time with no Koudai around to compete for her.
Takuya’s long kiss with his “voluptuous” daughter, his last action before leaving Sakaimachi behind, is the alpha and omega of YU-NO. Yu-no states that only sex with her father will enable her to complete the rite of the priestess with Grandmother:
Not incidental to how the characters save the world and resolve YU-NO’s conflict, the parent–child incest romance enthroned in the title of the video game, drip-fed from start to finish, is pivotal to the story and arguably more important than even the Reflector. The purpose of the Reflector, anyway, as Koudai establishes in the Prologue, is fulfilling Takuya’s incestuous desire for his mother. YU-NO not only vindicates semi-pedophiliac parent–child incest as a romantic fulfillment of the bonds of family powerful enough to transcend time itself—YU-NO is the story of how parent–child incest saves and creates the universe.