The answer popped into my mind.
Just one.
A narrow answer, like the eye of a needle.
"But before I tell you, there's something we need to address."
"... What is it?"
"Your fist. We need to understand its exact conditions of use."
In fact, in terms of offensive power, Kangchan's ability is the strongest I've seen among players. The impact of a single blow is comparable to the master of a city who has activated the heart of an island.
Naturally, Kangchan's fist is the key ability when tackling floors 3-5.
Right now, I'm merely guessing that it can be used 'once', but understanding its exact conditions of use is crucial.
"... Then, I guess I need to explain it to you."
Kangchan, answering my question with another question.
"I assume... you're not a regressor who can only return once. You probably return repeatedly. You spoke to me immediately upon entering floors 3-5 without even looking around."
"We need to know the conditions under which your regression point changes. Do you decide? Or is it predetermined? Can it be reset?"
Kangchan is asking about my regression ability. I hadn't revealed anything about my regression ability, mainly because he had been so forthcoming with his.
"... Why do you want to know?"
"Why not? Aren't you planning to regress anyway? What's the harm in telling me?"
He had a point. The memories would disappear once I regress, so there's no harm in telling. But still... saying 'I regress when brushed against' felt a bit awkward. It wasn't a logical thought, but rather a gut-level aversion.
"... I regress when certain conditions are met. The point of regression is set to the moment I first enter each floor."
"You asked about the penalty for my fist, but you're also hiding specific conditions."
"Just consider it a mutual non-disclosure."
Kangchan shrugging.
"... Okay. Next, I want to know in detail what happened after you entered floors 3-5."
"Why?"
"Shouldn't I be able to judge whether or not your plan is feasible? I've already told you my story."
"Um, excuse me..."
During our intense exchange, a clueless person named Glasses Jun interrupted.
"There's a lady waiting... you should go now..."
"... I will. In a moment."
"Okay, got it..."
With a single glance, Kangchan subdued Glasses Jun and shifted his gaze back to me.
"You don't have to tell me if you don't want to. Or you can lie. After all, if you 'regress,' I'll forget everything. Actually, you could regress right now. You got the information you wanted. But remember, a plan that seems perfect to you may have flaws when viewed by a third party. I have some insights to share."
Kangchan.
Contrary to my initial impression, this guy seemed quite sharp. And he was currently being cooperative.
I'm not sure about his intentions, but his help might be useful.
"... Let's start from when I first entered the 3rd floor."
So, I began recounting my experiences upon entering floors 3-5.
It felt uneasy to disclose the fact of my regression and share past events, but Kangchan was right. A plan that seems perfect to me might have flaws in another's eyes.
"... After seeing blood on the golem's fist, I regressed."
About 10 minutes must have passed.
I finished my story, Kangchan was deep in thought with a stern face, and Glasses Jun, wondering why we hadn't come yet, sneaked a peek but quickly retreated due to the tense atmosphere.
"... I listened well."
Kangchan nodded with an almost unreadable expression.
"Firstly... On the 3rd floor, it seems you can only use the 'fist' once."
"Are you sure?"
"To be honest, giving you too much information makes me uncomfortable. But I'm not lying. Floors 3-5... they really don't suit me."
"... I see." It seemed Kangchan understood the implications of giving information to a regressor, and he didn't appear to be lying.
If he could use his 'fist' twice, things would become much, much easier. But just once? It's undeniably a letdown.
"By the way, including you, the other three seem quite strong."
Kangchan turned to look in the direction where Dok Suhee and Glasses Jun were waiting.
"For me, the 'fist' is akin to a last resort. After using it, it's almost like I'm walking around with a target on my back."
"But you used it in the arrow trap, didn't you?"
"I probably had faith. Faith that, with you guys, I could survive to the end even after using my ability."
Kangchan in the past probably observed others closely. Excluding his 'intimidation' trait, Kangchan, who was virtually powerless, always had to observe others.
From personality, strength, to thought processes. Considering all of this, Kangchan concluded that he could trust our party and would use his ability midway. (Kangchan wasn't in a position to pass the trap hallway easily either.)
Moreover, he had his 'intimidation' ability as a last resort, so he must have been confident about surviving.
"... I didn't expect the golems that don't react to life force to jump out though."
That end wasn't pleasant.
"... I think I've played all my cards. Now it's your turn."
Kangchan looked straight into my eyes with his dark pupils.
"Let's hear your plan."
"... Alright."
After a brief contemplation, I began to explain my plan.
The essence of my plan was simple.
To understand what these four of us have, analyze the obstacles ahead, and use each asset where it's most effective.
It wasn't an ambitious plan. Just a change of perspective.
"... Your willpower is the crux of the plan."
That was Kangchan's response after hearing my entire plan.
"It looks like it has a high chance of success, as long as you don't falter."
In reality, that was the biggest issue with this plan.
It's a battle of whether my willpower can withstand or not. But I couldn't see any other immediate solution.
"... I'll support you."
Kangchan nodded slightly and then slowly rose from his seat.
He relaxed his shoulders and fixed his gaze on me.
"Now, regress."
A fist wrapped in light. A fierce aura emanating from him.
The precursor to Kangchan's 'fist'.
"... I was planning to regress anyway, but is this really necessary?"
Of course, I was thinking of regressing, but it hurt a little to see his attitude change so suddenly.
"Think from my perspective."
Kangchan shook his head.
"You might have a special skill to peek at my status, or you might have guessed my ability and tried to play mind games."
"Why do you think I told you about my past and my abilities so easily?"
Just like a regressor, the moment Kangchan's true nature is exposed, a clear counter exists against him.
Numbers.
Merely overwhelming him with numbers can defeat him. There might be some sacrifices, but once his punch is used, he's virtually powerless.
So, the moment Kangchan revealed his ability, he had no intention of letting me go easily.
"... If I'm not a regressor, you'd be trapped on the 3rd floor, right? We can't proceed without all four of us."
"Once my 'true nature' is exposed, I'm as good as dead. I was gambling in my own way..."
Kangchan stopped mid-sentence and chuckled.
"No, I'll be honest. At first, I had doubts. I took a gamble like I just mentioned... but now, I believe in your regression. It's both my intuition and a conclusion drawn from observing you."
"... Then why are you doing this?"
"I'm trying to score points."
"... What?"
"Ever thought about how others feel when they meet a regressor?"
"You're like a natural disaster or an unstoppable force. Unless there's a way to seal you forever, avoiding you is akin to committing suicide."
Kangchan smirked.
"I'm making an appeal to you. I'm not some naive idiot. I'm someone who can be useful to you, and, furthermore, to humanity." Kangchan was speaking.
He claimed that he had quickly grasped the situation to this extent, priding himself on his perceptiveness.
He believed it was more rational to leave and utilize a power rather than expose it here and there, leading to its complete downfall.
"... I wondered why you spoke so candidly at first."
So there was a plan all along. I thought he was just being thoughtless.
"No, it's not just that I didn't want to let you go, so I told you."
However, Kangchan shook his head dismissively.
"I also wanted to see how you'd react to my story. Just as you observed me, I observed you."
"And from what I saw... you're someone I can trust."
Both the present me and the past me would think so.
Saying that, Kangchan gave a shy smile for the first time.
"... So, I'll support you."
The light in Kangchan's fist slowly faded.
"... Thank you."
I nodded slightly and then regressed.
[ You have taken damage. ]
[ You will regress to the moment you first entered the 3-5th floor. ]
"... Wake up, rookie."
"... Whew."
Before executing the 'plan'.
First, there was something I wanted to test out.
"Let's go."
Golem.
I had to face that creature once again.