Then there were nun Nun of Your Business Mystery Series, Book 1.

My name is Sister Trixie Lavender, and I'm an occasionally possessed excommunicated nun. Okay, that's a lot to swallow at once. But it's true I was booted from the convent after doing something unspeakable. Something I had no control over. Something that lives inside me to this day, exploding out like that chestburster in Alien when I least suspect it. But I have help. My amazing friend Coop-the demon who saved me from an ugly end-remains by my s...