Stuck in this nightmare with you NSFW
"Wait, go back to that shop. I wanna talk to that girl, she looked cute."
Katrja sighed. "For the last time, I'm on a schedule today. I don't have time to indulge you on every single attractive woman we come across."
"A schedule to do what?" Lixia's voice echoed through Katrja's head as clearly as if the demoness had been whispering right into her ear. "If this is about fighting more sin eaters..."
"I'll remind you that neither of us wants the sin eaters to grow stronger. And both of us want to know how they tick." Katrja twirled her staff, blinding lines of brilliant fire, glinting ice, and arcing electricity visible in its path. "Well... I do. And I make the decisions around here."
Lixia sank into a sulk in Katrja's chest. "Tala lets me drive sometimes."
"You were the one who asked for this arrangement. I should hope I don't have to remind you that I'm not Tala."
Katrja felt her eyes twitch downward, toward her bust.
"Oh, I know only too well," Lixia said, releasing control of Katrja's face.
Katrja pursed her lips. "Are you trying to imply something, succubus? I'm quite secure in the size of my chest - though I could always make it bigger."
"Right! So let's head back to the shop and talk to that girl!"
Katrja shook her head. "Vivisection of sin eaters now. Flirting with random girls later, and possibly never."
"Straight through the heart," Lixia wailed. "Why do you attack my favorite things like this? You're worse than my sisters! Cruelty beyond compare!"
"Do go on, I love compliments," Katrja teased, a flirtatious lilt to her voice. "Talk about how cozy my heart's darkness is again."
"I don't want to now." Lixia blew a raspberry from somewhere inside Katrja. "You're ruining it."
Katrja grabbed the amaro's reins, keeping a close eye on the skies for her prey. "Didn't you tell me I had nothing to worry about from a composed, confident, mature succubus like yourself?"
"I have been a perfectly behaved guest."
Katrja snorted. "Other than the one time I let you out and you ate that girl and nearly got caught at it."
"I can feel my aether melting off me, I needed the boost, subtlety wasn't really the ideal... And hey! You wanted to eat her too!" Lixia was pouting, Katrja could feel it.
"Yes. I wanted to eat her. That was the whole reason I was angry at you. Do you listen to anything I say?"
Lixia pretended to mull this over. "Mmmm... I try not to..."
Katrja groaned, scanning the skies. "Honestly, I ought to let the sin eaters have you. But Tala would be upset with me if I did that, so I'm stuck with you."
"Love you too~" Lixia teased, and Katrja got the distinct impression that Lixia was blowing her a kiss.
"You know, if I'm ever tempted to make a pact with a demon again, just remind me of this experience so I remember how bad of an idea it is." Katrja nudged the amaro with her knees, soaring through the skies toward her target. It was probably nothing, but...
Lixia huffed. "I've been helping. Don't you feel the void strength in your spells?"
"Yes. Unfortunately, it seems to just fill the sin eaters with more energy, so you need to stop helping." Katrja leapt from the amaro's back toward the ground, sketching a circle of ley lines down below and vanishing to end up right at its center.
"Wh- That's your own fault!" Lixia protested. "You said you wanted to try to see if you could get one to be overwhelmed by shoving aether of a different aspect down its throat! Any idiot could have told you that wasn't going to work, and an idiot did! Don't blame me when it just gets bigger and scarier!"
"Don't remind me." The girl Katrja had been trying to protect - a fool prone to wandering off on her own - had taken time out of screaming to point out that her plan seemed like a stupid one. This time Katrja's plan was a lot more simple. Scorch its hide until it melted. Accelerated by the preplaced circle, she unleashed fireball after fireball.
Lixia sighed, curling up in a ball inside Katrja. "You're no fun!"
"I am sorry that my attempt at saving your life is not sufficiently amusing," Katrja said through gritted teeth, barely maintaining focus on her spells as the sin eater came in for a strike. "For my part, I'm sorry that what I thought to be a fully grown succubus with an age measured in the thousands is in fact a child who needs constant amusement even as I fight for my life, and hers..."
"Tala can't get here soon enough," Lixia grumbled.
On this, at least, they agreed.