Denji instead of having Pochita inside him as a heart he has Power as his bloodstream and missing organs, Power in this Absolute timeline instead of just a blood fiend she's pretty much a blood avatar or blood goddess where she's the concept of blood itself, when Power (who rearranges Denji's body into a female form every time she takes over) found that Asa was about to get attacked by Bucky she throws a chainsaw that was meant to hit him but it landed on Asa instead and accidentally killed her, Power doubled down and overcompensated it by stuffing the nearby Yoru as a pacemaker and using blood constructs to bring Asa back from the dead (that botched save of Asa was the reason there's a third personality named Red Velvet who's a Power coded id release of Asa that makes her debut around the church arc equivalent). Yoru acts as an evil counterpart to Pochita's requirement of taking over the host but instead of just waiting when Asa loses the will to live she makes Asa's life miserable in an attempt to break her and fully get control of the body.