Ka'el?

Think, think. He's just standing there, watching us right now. But this is one of the biggest threats the game had. There was a reason actually encountering him, well, demon him, was almost never seen. My mouth is dry. My shield feels too light in my hand and too heavy on my arm at the same time.
And even worse was the fact that he is smarter than the game. He was only coded to turn on Lancer if he couldn't get any party members within five minutes. But here he is, at full power from the start. No ramp up. No tells.
There has to be something that I can do here, we don't stand a chance like this. Even a fully buffed and prepared party would have a hard time facing him. We are neither. No buffs, no plan.
My brain is working overtime, pulling all the game knowledge I have about Ka'el and his contracted demon. Item descriptions, half-finished codex entries, off-hand NPC lines. Anything. I try to string the scraps together into something that might save us.
"It's no fun if you all just stand there in shock." Demon Ka'el sighs, his distorted voice sounding like it's coming from deep inside my head. It vibrates behind my eyes.
"Should we run?" Ranger whispers.
"Think about how long it took us to walk here," Captain hisses. "Then think about how it took him two goddamn seconds to do that."
No one dares to actually move, almost like we're prey, hoping that by standing still the predator won't pounce. And is that thing a predator. My skin prickles. Priestess' hand is clenched so tight her knuckles are white. Retainer presses herself smaller, hood shadowing her face.
"I'm disappointed." I can feel his gaze on me. "After all the trouble you gave my host and his brother, I expected more."
The simple act of him pointing his spear at us sends chills down my spine, I can sense it's having a similar effect on the rest. The point doesn't glow. It doesn't need to. It just exists, aimed, and every instinct I have screams.
He lowers his stance even more, his legs tensing.
"Wait!" I shout. "How about a trade?"
"Oh, so you do have a backbone." He responds. "But, no. What would I even want from you trashy heroes that I can't just take once I've killed you?"
He's almost ready to charge. My tongue moves before my fear can stop it.
"You're Varketh, the Demon King's brother right? I offer knowledge to the Demon of Enlightenment!"
Please don't let me be wrong about this. It's never been confirmed, but there are a few lore hints you can find scattered around that give this theory credit. An old tome in the abandoned library, a cryptic poem carved into stone on a basement level—pieces of a puzzle I'm now betting our lives on.
"You dare, speak my title, speak of my brother, and then offer me," he spits. "ME, THE DEMON OF ENLIGHTENMENT, KNOWLEDGE?"
Surprisingly, he pulls back his stance, lowering his spear. The air loosens by a hair. A heartbeat returns to my ears.
"Speak then, what do you offer?" He looks down on us like we're insects, begging not to be crushed. "And don't disappoint me."
"We offer you knowledge of our world."

"I abide by the contract. I will not harm any of you until we conclude the meeting, and if it satisfies me, I will allow you to leave." Varketh announces from the top of the ridge, before slowly heading towards us.
A demon abiding by a contract is the strongest way to bind them, which means he has to be true to his word, or he'll be forcibly removed from this plane of existence. That's the rule. That was always the rule. Please still be the rule.
Everyone breathes a sigh of relief as it hits us, we're safe, at least for now. The tension doesn't vanish, it just sinks lower, coiled in our stomachs.
"Well then, how about we get comfortable for our little exchange?" He acts and speaks in such a regal way, completely different from Ka'el.
He snaps his fingers as he reaches us, summoning a chair for each of us, and a gaudy looking throne for himself. As he takes his seat, he gestures for us all to sit.
Everyone is still a bit apprehensive about what's going on, so I take the lead and sit first, starting a cascade of everyone doing the same. No one takes their eyes off him.
"So, you offered me knowledge. Let's hear it, what do you offer me of your world?" A smile spreads across his face and he leans on his elbow.
"I'm a Medical student, so I offer you that knowledge." I start.
"What really?" Priestess exclaims before covering her mouth. "Sorry, I'm also a Medical student, so I also offer that knowledge." She recovers, cheeks pink, but steady.
"I offer you my knowledge of Engineering and Robotics." Captain adds. Her voice is clipped, controlled, like she's presenting in class.
"I may be younger, but I can offer you my history knowledge." Ranger quietly joins in.
"Hmm, a wide variety of strange subjects. Delightful." Varketh laughs, before pointing at Retainer. "And what about the child? I know my host had it out for you, but I feel no animosity towards you, if your offer is worthy."
"Wait, you can see her?" Ranger asks.
"Petty tricks don't work on me, Heroes."
Shit, I was afraid of this. Retainer is an NPC from this world, she has nothing to offer him. I subtly glance at the girl sitting next to me, her eyes wide with terror. She shrinks under his attention like it burns.
"I'll offer to answer any questions you might have in place of her." I interject.
"And why would I accept that?" He glares at me.
"Surely a deeper understanding of our world is better than what you might glean from a young child."
Please accept. Surely he must find the offer of otherworldly knowledge more enticing than trying to screw us over. He would be able to easily claim that Retainer's knowledge is insufficient and use that as a basis to attack us. My palms are sweating. I keep my voice level.
"I like you Paladin." He laughs. A deep hearty laugh. "No one has tried to talk back to me in many years. I accept your offer."

Now, there is probably an unstated downside about telling a demon all about our world and how things work there, but desperate times call for desperate measures. If we live, I can regret it later.
First up, Priestess joins me and we give him as much information and details about our studies and our medical knowledge as we can. He sits and listens intently, actually looking intrigued about everything we're telling him. We keep it simple: how blood moves, how bones knit, how tiny things you can't see make you sick, how to keep a wound clean. Triage. Why washing hands matters. He interrupts only to clarify a term, eyes bright like a student hungry for a new book.
Next, Captain replaces Priestess while I stay in my seat. Now, I have no clue about anything to do with Engineering or Robotics, but I help Captain explain things in a way that Varketh can grasp, instead of her technical and lingo filled explanations. Gears become teeth. Current becomes a river he can turn on and off. Code becomes instructions whispered to obedient golems. She talks about ethics, too. He listens, expression unreadable, tapping one clawed finger, thinking.
After Captain finishes her very passionate explanation about the ethics of using robots as workers, Ranger swaps with her and takes the seat next to me.
History at least is a subject that I can join in talking about, at least more than Engineering. Varketh listens intently as we tell him about the history of our world. From simple inventions, to world events and wars. How words shaped borders. How one spark can set years on fire. How people repeat themselves even when they swear they won't. He asks about causes, not just battles, and smiles when we talk about printing presses and ideas spreading faster than armies.

"Ah, so much. You have given me so much." Varketh thanks us.
He stands, and snaps his fingers again, removing the chairs. The sudden absence makes my knees wobble.
"Does that mean?" Ranger starts.
"You're satisfied?" Priestess finishes.
"As much as it pains me to let you go," Varketh sighs. "I'm very satisfied."
We all breathe a collective sigh of relief. Meeting such a demon and finishing the encounter without a single casualty is an even better result than I thought we would have. My shoulders drop. The first pinprick of hope returns, foolish as it is.
"Unfortunately… " I don't even have time to react before his hand grabs my throat, lifting me up.
"But…" I choke out. "The contract."
"You should know by now." He leans in very close. His breath is cold. "I'm a special deal."