The Big Four in The Host

Merida Dunbroch refuses to fade away. The earth has been invaded by a species that takes over the minds of their human hosts while leaving their bodies intact, and most of humanity has succumbed. Rapunzel, the invading 'soul' who has been given Merida's body, knew about the challenges of living inside a human: the overwhelming emotions, the too-vivid memories. But there was one difficulty Rapunzel didn't expect: the former tenant of her body refusing to relinquish possession of her mind. Merida fills Rapunzel's thoughts with visions of the man Merida loves - Hiccup, a human who still lives in hiding. Unable to separate herself from her body's desires, Rapunzel yearns for a man she's never met. As outside forces make Rapunzel and Merida unwilling allies, they set off to search for the man they both love. (I do not own The Big Four or the Host, also includes Merricup and Jackunzel but with a twist!:))