That's why Fein also had to find reliable allies that could help him fend for those threats in the future.

'It seems I need to build a similar organization like SHIELD in the Marvel in this world,' Fein thought jokingly.

Of course, he won't do such a thing. He only cares about his friend and family the most. At the very least, he would try his best to fight enemies with similar strength to him.

"Let's start your sister's examination," Gregory said. He went to the door, stretched his hand, and pulled it. "And also see the supposed damage you've done in the Underground Base"

After saying this, Gregory walked out of the office.

"Dude, what damage did you do? Is there something that I didn't know about?" Michael looked at Fein and his sister and asked with curiosity.

"Forget it. It's not worth mentioning at all." Fein scratched his head awkwardly.

Fey stared at his brother with dissatisfaction and said to Michael. "It's better if we follow captain and see it for ourselves."

She walked out of the door briskly and gave Fein a look before she follow Gregory below.

I look at you; you look at me. Michael and Fein stared at each other awkwardly before laughing their ass off the next second.

"Well, let's go. It's just my sword's new ability." Fein said casually, "And I just miscalculated a little." He chuckled.

"A little? Hehe... It seems you've really messed the place up," Michael chuckled, which made Fein a bit speechless.

'I just said that it's just minimal damage. Why don't they trust words? Where's the trust between brothers go?' Fein couldn't help but sigh.

Just like that, the two of them follow the two, walked down the stairs, came past the reception area, greeted the only female member of their team, and walked through the entrance of the Underground Base.

When the two went in, they saw Gregory talking with Fey. Fein tapped Michael on the shoulders. "Go easy on my sister, okay? Although I doubt that you can manage to hit her."

"You are that confident with your sister?" Michael raised his eyebrow and paused. He looked at Fein and asks, "Is her ability that incredible? And what rank is she now?"

"She just ascended to C rank. So she's currently trying to adjust to the sudden advancement of her strength." Fein answered nonchalantly.

"What she's already C rank with her age!? That's the same realm as Captain!" Michael's eyes dilated with surprise. "Didn't she just become a degu user last year?"

Fein chuckled seeing Michael's skepticism. "No, it's not what you think about. Although she's also talented, much of her growth is the result of the training equipment that I made for her and potion that boosts that growth of physical body and degu energy."

He took out the 'Purple Yen' potion on his inventory and says "In fact, If I had this when I just started I would have already become S peak rank now."

"You really love your sister that much..." Michael stared at the purple potion. "I knew that you were a scientist, but to be able to invent something like that. If have that potion, could I breakthrough in A rank in advance?"

"Certainly, with your talent and this potion, your training speed would triple." Fein pushed the potion on Michael. "Take this. I already intend to give all the members one." Then he looked at Gregory in the distance and sighed with regret, "Unfortunately, the Captain won't enjoy the same benefit because he's already past his prime. The potion would have a limited effect on him."

Michael took the potion and scrutinized it. "So it's the one that helped your sister to ascend from F to C rank in just a year and a half?"

Fein shook his head. "It's a combination of different factors. Her talent, this potion, the pressure she experienced in the past year, and the equipment that I made for her." he paused for a second and continued. "And it only looks fast because the potion's effect is stronger in the lower ranks such as F to B. But if an A rank and B rank took it, the effect won't be the same as in the lower ranks, and it would be a tad bit slower. Nonetheless, the boost in training speed would still be more significant than not taking one."

"Experienced?" Michael caught the keyword on Fein's statement.

"Yeah." Fein sighed. "A group of abominable hunters that hunts degu users targeted her. That's why she has no choice but to exhaust herself just to get stronger in one year."

Michael clenched his fist and looked at his Fein with guilt. "I'm sorry I didn't know." he stared at the ground and breathed deeply.

"Don't worry about it. The servants of Viscount Lucius had wiped them out from the face of the planet already." Fein replied and patted Michael on the back lightly.

"Now I knew why she's unnaturally more mature than her own age." Michael couldn't help but feel pity that such an age had already lost the innocence she should naturally have.

Fein nodded. When he saw Michael's expression, he knew what he was thinking. "Although she became mature earlier. It has a good side that, with the loss of her naivety, comes wisdom that her peers lack. And this would help her survive in our line of work. After all, people with milk in their mouths are the ones who die early."

"Hmm... If you put it that way, that really makes sense." Michael stared at Fein with a weird gaze. He's fascinated by how his friend's brain works to think in such a direction.

"Don't look at me that way." Fein threw a light jab at Michael's shoulder.

"Sorry," Michael apologizes. "By the way, what equipment did you invent? Could you also make me one? I want to ascend to A rank as soon as possible or else I would only eat the dust behind you. I don't want to be left behind and only look in the distance." He quickly changed the subject.