The way this is set up reminds me of a romance novel. Two people, alone in a room, the heater is broken and they need some way to warm up. So now Krista gets to be Levi's snuggle bunny and help keep him warm after the shower ran out of hot water.

[His eyes narrow as her rolls out from the towel and onto her thighs] I think something is off in this sentence. Is that "her" supposed to be "he"?

This is lovely. You write so well it's no wonder this seems like something from a romance novel. And now they are all warm and toasty and ready for a nice, long nap after the fun they had.

That. Was. Amazing. I was so hoping there would be LeviXKrista stories around here, and alas there are! Good ones, at that! So, obviously, I loved it. And I even saw that you had more. Now I MUST read them!

Ooh, running out of hot water in the middle of a shower is never fun.

I'm sure I'e told you this before, but: "it's" is a contraction of "it is". Possessive pronouns in the English language never have an apostrophe! (his, hers, yours, ours, theirs, its.)

He didn't know who was knocking on his door and told them to come in while he's only wearing a towel? XD

Hmm, it's Krista and she's cold too. I wonder where this is going... (No, that was sarcasm. I can pretty much tell where it's going from here...)

Well, they're both warm now, lol...

You started the fic out in past tense, then slip randomly between past and present tenses in the middle, and have the half-ish of the fic in present tense. You probably want to go back and put it all in either past or present.

I like how the story fits partially with the timeline. I do enjoy rivakuri and it's hard to find good tics on them, so great job.

Your muse is an evil spirit.
A lust spirit to be exact.
Look up spirit attachment.
Evil spirits influence their host human's thoughts.
You are infested with demons.