To summarize the Guild Master’s explanation:

In this world, a Demon King appears periodically. Whenever the Demon King is about to emerge, it is always preceded by a surge in monster attacks across various regions.

According to The Sage’s prophecy, Takana Mika’s help is necessary to suppress the monsters and repel the Demon King.

The Guild wants Mika to register as an adventurer, gain experience by defeating monsters, and eventually fight the Demon King when the time comes.

Since Takayuki Yamano came along as well, they’d like to ask him to help with monster subjugation too.

“Um… even if you tell me to fight the Demon King, I don’t think I can do that. I’ve never fought before. Monsters might be manageable with insecticide, but I can only come here two days a week for six hours a day.”

“Dada has already reported about Mika’s job. We’ll handle disposing of the monsters on the dungeon’s lowest floor and gather items for Mika to take back to her world, packing them in a box. Using the Door should save time for transportation.”

“Hold on a minute. Items taken to the outside world originally belong to Mika’s territory, don’t they? They don’t count as payment. Moreover, Mika is here under a contract with our company, so anything taken out through the dungeon’s Door can’t be treated as her reward. What exactly are you offering Mika herself?”

The Guild Master groaned, deep in thought for a while, then spoke as if he had made up his mind.

“Then here’s the deal: All items collected from the dungeon’s lowest floor will be placed in the box Mika takes with her. This is a substitute for her work, but since it’s a request from us, the kingdom and the Guild will cover the expenses. For every monster Mika slays, appropriate compensation will be deposited into her account in this world. Additionally, if she agrees to accept the Demon King subjugation request when the time comes, we’ll lend her a key to a separate Door leading to her world—one not connected to the dungeon. Upon successfully defeating the Demon King, ownership of the key will be transferred to her, and Acid will prepare a residence for Mika. That way, she can come here anytime, use her earnings to buy things, and take them back through her own Door.”

“So, the condition is that she must agree to fight the Demon King, is that it?”

“…Well, yes. But even as things stand now, there’s no issue with her using this world’s money to eat, drink, or shop.”

“Um, can I ask something? …Are there multiple Doors to my world that have been discovered?”

“Yes. Very rarely, people who find the keys end up going through. Many die the moment they step through, while others are captured, caged, and enslaved. I’ve heard it’s a terrifying demon realm. Based on the few survivors’ accounts, those Doors have been sealed, and the keys are generally kept by the royal families of each country.”

“Enslaved? Enslaved… kobolds… with collars… cages… I see!”

“It really might be a demon realm!”

“Even so… for someone from such a place, it’s fortunate that the dungeon boss is you, Mika. We truly hope for your cooperation.”

A house and money in this world, plus her own personal Door (not Warehouse No. 4)—if she brought the children here, they’d be thrilled.

But the Demon King…

Just as she was about to respond, Takayuki raised a hand to stop her. It seemed he would handle the negotiations from here. For Mika, who tended to answer without thinking too deeply, his help was a relief.

“One thing to confirm—you don’t necessarily have to kill the Demon King, right? As long as you repel them and minimize damage to this world?”

“Of course. There are almost no records of a Demon King being killed in the past. Besides, the Demon King likely comes from Mika’s world. Rather than slaying them, we’re hoping Mika can somehow pacify the Demon King and seal them away in her world.”

“From my… so, the Demon King is human? An ogre?”

“No, their appearance varies, but most Demon Kings are massive beings, nothing like ogres.”

“A really fat person, maybe?”

If they were human, she might be able to reason with them. Maybe she should install a translation app just in case…

“So, how much damage needs to be prevented for the request to be considered complete?”

“Hmm… let’s say within three days of the Demon King’s appearance, before a second town is destroyed.”