Leaving the children's room, they returned to the entrance hall. There, they encountered a zombie servant, which Iris dispatched. At first, she was scared, but after psyching herself up, she was able to use her short sword to slay the zombie. Perhaps due to the holy attribute imbued in the weapon, it only took three strikes to purify the zombie, even without targeting its weak spot.

Now, they were back in the central entrance hall of the mansion's first floor. There was a staircase in the center leading to a room beyond it. As of now, there were only two keys as clues to escape.

"Let's go to the room in the back of the center," she said.

As expected, the door was locked, but they were able to open it with a key they had. Inside, judging by the size, it seemed like a place for holding meetings. Looking up, they saw three ninja zombies clinging to the ceiling. Judging from their appearance, they were indeed ninja zombies.

"Fin, Iris, you know what to do. Take them down without hesitation," she said.

"Yes!" they replied.

The three ninja zombies jumped at them all at once.

As expected of ninja zombies, they were quite fast. However, they leaked a bit of killing intent. If that was the case, Fin and Iris should be able to handle it. She was able to slay them easily, but I wondered how Iris was doing. Iris seemed to understand that her ability was the lowest, so she just kept receiving the ninja's swordplay without moving. Then, she found a slight opening and was able to purify the ninja with a short sword that concentrated magical power on that point. When she looked at Fin, she seemed to have some trouble. As she got used to the enemy's speed, she regained her composure and was able to counterattack and slay the ninja. It was a decent performance.

"You two seem to be fine," I said.

"Master, it seems like there's nothing in this large room," Iris said.

"It's not like that. They called themselves ninja zombies, but if there are ninja zombies, then there's a high probability of hidden passages existing," I said.

"Huh? Hidden passages?"

"Yes. There should be one in Redenburg as well. In case the castle is attacked by evil forces, there are emergency hidden passages. When you become a master ninja, you can completely hide your presence and killing intent, and assassinate someone using a hidden passage without anyone noticing. If there are ninja zombies in this mansion, then there must be a hidden passage somewhere. As a classic example, it could be behind that hanging scroll over there."

"Oh, onee-sama, I found it, but it's locked with a padlock."

"Gack, why did they have to put it in such a predictable place?"

"This key won't work. The other entrances lead to the garden we saw earlier and the opposite side, but they're also locked with padlocks, and the key doesn't fit. There's no point staying here any longer, so let's go back to the entrance and either go to the second floor or think about going down the right corridor."

As I was pondering my options, I heard, "Oh, Onee-sama, there's a ball on the stairs. I'll go get it."

A ball? There wasn't one there a moment ago. This could be bad, a trap!

"Finn, stay away from the stairs. Iris, come back here."

Iris was about to pick up the ball in the middle of the stairs when suddenly, the uneven surface disappeared, and a large trapdoor appeared on the first step of my staircase. This is bad! I tried to grab onto a protruding section, but at that moment, Iris slipped and fell down the hole. There was nothing I could do.

"Noooooooo~!"

"Finn, I'll toss Iris over to your side. I'll attack from underground, so you guys team up with Jin and Rikka and attack the first and second floors. I'll take care of Iris. Finn, catch her~"

I tossed Iris over to Finn just as the trapdoor closed, and I fell into the darkness below.

Iris's Point of View

It was my fault that onee-sama fell into the trap. If only I hadn't gone to the second floor without caution...

"Iris, can you hear me? Iris!"

"Y-Yes!"

"Don't have time to feel down. Master will be okay since he's an evil god and won't die. There's no point in regretting what's already happened. Let's just be careful from now on. We'll team up with Jin and Rikka and attack together with four people."

"Uh, yes, I see. Let's switch gears."

I see, let's make use of this failure next time.

"It's 30 minutes until the meeting time. Let's check the hallway on the right from the entrance until then."

Together with Finn-nee, we walked fearfully down the hallway on the right and found a room and a door leading outside. We were able to enter the room normally, where there were many clothes that were similar to the ones the samurai zombie was wearing, but with some differences. Was this a dressing room? We searched the room, but couldn't find any items.

"Finn-nee, what should we do with these clothes? They don't seem useful at all, do they?”

“Well, they might come in handy for something, so let's take them all just in case."

When did this mansion come into existence? According to one-sama, it was from around 500 years ago, during the time when her older sister from the previous world was still alive. She said that they might have been pulled into this world around 500 years ago. If possible, I would like to purify everyone. When we opened the door leading outside, we saw a road leading to a large house in the distance. That was the house we saw from the mansion gate. Onee-sama called it a dojo. I wonder if there's anything there?

"Scream---! Wait, that's not a zombie, is it?”

“Iris, let's go check it out." When we entered the dojo, there were about 15 people in samurai zombie-like outfits sitting formally. And three adventurers were lying dead. What's going on here? "They were killed by zombies, right?”

“I think so, but there's something strange... huh? The three adventurers are moving!" Ugh, it's so creepy. A person whose left shoulder to right thigh was slashed, a person whose head was almost cut off, and a person whose left chest was pierced and impaled were slowly walking towards us, making strange noises. "Finn, are we being targeted?”

“Yes, we are.”

“Uhhhh,”

“Ahhhh,”

“Uuuuuu."

Finn started moving, so I followed suit.

"Iris, I'll take the zombie in front, and I'll take the two in the back.”

“Yes!"

When I went to the adventurer zombie, he attacked me with a sword. Huh? But he's slow. This dungeon is A-class, so this adventurer should be A-class too, but why? No matter how many times he attacked me, he's slow. In that case,

"Slow! There!"

I stabbed a short sword into his neck from the big gap on his right side. The adventurer zombie was purified and collapsed. It's kind of disappointing. Finn was also stunned because she could easily purify him. Maybe he wasn't completely turned into a zombie because he had just died?

While we were thinking, an old man zombie with hair up to his shoulders and a mustache came towards us. Oh, I didn't notice at all. That's right, there are fifteen samurai zombies here! Huh? Come to think of it, I haven't felt any signs of them attacking since earlier.

"Uaaah, do you want to compete too? If you beat five of us, I'll give you the famous sword, Kotetsu [Izayoi], passed down in my dojo. How about it?"

Uh, there's no way we can beat five of them. But these people are also wandering around the zombie house.

"---- I can tell that the Kotetsu [Izayoi] placed there is quite powerful. Judging by its length, it's perfect for Iris. Let's accept this challenge!"

"That's just reckless! Let's at least wait until we meet up with Jin and Rikka before coming here. Then I think we can handle it."

"Yeah, you're right. It's just the two of us, we might not be able to handle it if something happens. Alright, let's cancel the match."

"Ugh, then leave from here!"

Finn and I left here together and returned to the entrance of the mansion.

"Finn, it's crazy to try to beat five of them. The zombies we fought earlier had a lot of strong evil spirits coming from them."

"Yeah, but I want to fight. I want to see how far I can go with my current strength."

That's reckless.

"Let's at least consult with Jin. If we make the wrong choice, we could end up like the adventurer from earlier."

For now, we left the entrance and waited for Jin and Rikka to come back at the gate of the mansion. They returned in about 10 minutes, and we explained the situation about the missing onee-sama. Then, they made a grim expression.

"I'm sorry, it's because I went up the stairs recklessly."

"That's fine. Sasha-sama is not the problem. There's no way she could be in any danger. But Finn, are you planning to challenge the five of them? There's a possibility that you could die."

I see, everyone believes that they'll be absolutely fine if they have her as their onee-sama

"Yes, I understand. But I want to test my own abilities now. And the item we might receive if we succeed could be useful somewhere. Please let me do this!"

Oh, Fin-nee, you're really motivated.

"---Are you serious? A dojo, you say. I see, I sense a strong evil energy. With Fin as she is now, the chances of success are fifty-fifty. Let's move to the room where the statue of the goddess is for now. We'll have lunch there."

"Jin, can you make lunch?"

"I received a lunchbox in advance from Sasha-sama. She gave it to me so that I could have it in case we got separated."

"Oh, I see. Let's eat quickly and go to that dojo where you can beat five people. I want to see how far Fin can go."

As usual, Rikka is unchanged. Is it okay as long as she's having fun?

"Iris, don't worry. I'll help you if something happens. If that happens, both Fin and I will be expelled from the zombie house. But it's better than Fin dying."

"Yes, please."

Jin is reliable after all. After moving into the mansion and having lunch in the children's room, I asked Jin and Rikka about their progress.

When they were subjugating the zombies around the mansion, they said that initially they just cut them down without using the holy attribute, but it seemed that they kept coming back even after being defeated. So they started using the holy attribute to subjugate them, and it seemed that the same zombies didn't appear anymore. After all, it's necessary to purify all the zombies. Probably, in addition to fulfilling the mission, there should be a condition to clear the zombie house by purifying all of them. It's pitiful that the souls in the zombie house of Marco Ruins are trapped forever. Let's definitely purify them all. I definitely can't handle the zombies in that dojo. Fin-nee has to do her best. It's cheating when it's dangerous, but I can heal with magic.

"Alright, we're ready. Let's go to the dojo!”

“Hey, hey, Jin, can I try the five-person knockout after Fin is done?”

“Well, probably not. The purified zombies never returned.”

“Oh, right. Hmm, too bad. I'll just watch then.”

“Oh, you're getting smarter, Rikka. I thought you would challenge it before Fin did.”

“Boo, that might give Fin an advantage, but it's not fair if we don't do it fairly." Oh, Rikka seems smarter. Oh, Jin is patting her head.

"You've become smarter. That's right.”

“I don't feel happy even if I'm praised by Jin. I want to be praised by Sasha-sama."

"Rikka, I'll let you know when we meet up with master."

"Really! Thank you, Finn. Good luck."

We arrived at the dojo. When we opened it, the five-person elimination match began. Good luck, Finn!