The lovers meditated through the witching hours, as Dell's old book bid them. They held hands as the candles in the apartment burned low, smelling and touching each other, and watched themselves watch themselves in the mirror Rachel had moved in from the hall. 

"So..."
"... Mote it be," they whispered, when at last their time ran short.

"So mote it be!" the demon in the mirror cheerily agreed.

"JESUS FUCK, WHAT! WHO! GET OUT! OH FUCK SHIT!" Rachel replied, throwing herself backward with enough force to topple the couch. Dell, tonguetied, let the crashing furniture carry her down, then craned her neck up to stare at their visitor.  

Yep. Definitely, unmistakeably, a demon. Flowing, firey red tresses, pristine tan skin, a shirt and skirt combo that could have come straight out of a web search for "naughty librarian costume", the curves to fill them, and twin pairs of batlike wings on the backs of her head and torso.

"So!" the demon chirped. "As per the ritual, I'm here to get you set up with the Words and give you a starting tour of the Worlds, and, um, do you need a minute?"

Rachel stared at Dell, then at the demon, holding a finger out in front of her but not sure where to point. "No. Please leave? Please. This did not work. There is no way that stupid book worked. We are so fucked. Get away, get out of my fucking apartment, don't eat my soul, please?"

"Soul? Oh, one of [i]those[/i] worlds. No, no, listen! That's all made up, there's no price, your soul is fine, I promise! It's more like, um, do you have computers? I think I see a laptop back there? The multiverse is like a computer, magic just sort of programs it, and the only common link we've found is--"

A thrown boot interrupted the demon, shattering the mirror into a spiderweb of frosted cracks and shards. Her image vanished, the warm crimson glow ceased, and the apartment went dark and silent again.  Rachel, breathing heavily, ran as fast as she could into the bathroom. 

Behind her, Dell quietly picked up one of the shards of the broken mirror, staring down at it. Dreams of something better danced through her mind. A world, infinite worlds, a life without her partner - but then, Rachel hadn't even expected the ritual to work. Hadn't dared to hope for it. Had thought the book was stupid, the ritual was stupid, all this was stupid.

In such a multiverse, surely there was something - someone - better out there?  

Dell reached down to the largest shard, ignoring how it cut her fingertip. 

By the time Rachel was back, the living room was empty.