"Hah… that scared me to death."
Lux finally let out a sigh of relief. He'd really thought that the system, which always mocked him, had secretly sold him a fake product.
[Hehehe, Host. If you upgrade the system to Level 2, even better medicinal effects will be unlocked~ They'll further strengthen your physical attributes]
[As long as you drink that, even if you're scratched or bitten by zombies, you'll no longer mutate into a zombie]
'So basically, you only sold me part of it first, let me taste the sweetness, and then used installment-style purchases to lure me into investing more resource points?'
Lux said with a laugh.
[Not at all. The Level 2 potion and the gene modification serum are completely different things. Otherwise, it wouldn't be something you drink.]
The system hurriedly explained.
'Then why didn't you just list all the drinkable potions in the first place… instead of having HK stab my heart with such a thick needle? That kind of taste is seriously twisted.'
Lux grumbled internally.
[Upgrading the system to Level 2 requires 30,000 resource points. The Level 2 potion requires 200,000 resource points. Host, would you really have been willing to buy it back then?]
The system said disdainfully. After thinking about it, Lux realized he really wouldn't have been willing to buy the Level 2 potion outright.
[Besides, your original physical condition was far too weak. You simply couldn't withstand the transformation of a Level 2 potion. You had to use the Level 1 gene modification serum first to strengthen your body before you could endure the advanced potion]
[Host, please speed up your acquisition of resource points. Our side is currently in urgent need of resources. Otherwise, I will adjust prices upward depending on the situation in the future]
'Alright, alright. I'll collect resource points as fast as I can.'
Lux said helplessly.
In reality, the Level 1 system only offered a 100,000-point Tactical Doll summon, exchanges for various ammunition, firearms, and Level 1 melee weapons, as well as improving Tactical Doll ration refreshes.
But he had already found plenty of food. Relying on apocalypse resources alone was enough to feed the Tactical Dolls, so for now, he had no intention of spending resource points to improve ration quality.
Good steel had to be used on the blade. Surviving was the top priority right now.
And since the Level 2 potion could prevent zombie virus infection, it was clearly worth exchanging for.
In addition to generating antibodies within his body, it would further enhance all aspects of his physical abilities. This was obviously a great deal.
After all, he can only buy 20 vials of antivirus with 200,000 resources points, while this Level 2 potion directly produced antivirus in his body. No matter how many times he was bitten, it wouldn't matter anymore.
'Hey, why do I feel like you're trying to scam me again? What exactly is this Level 2 potion?'
Lux asked warily. Something felt off. There was no way such a high-level drug would have such a low-effort name. The more the system avoided explaining it, the more suspicious he became.
[This is commercial confidentiality. Of course, if the Host insists on knowing, you may pay 50,000 resource points as an intelligence fee~ I can open a little backdoor and tell you in advance~]
The system returned to its sleazy tone.
'No money. Goodbye.'
[How about I let you buy it on credit?]
The system asked temptingly.
'Anything borrowed has to be repaid. You make it sound nice, but you just want to trick me into spending more.'
'This is extortion, isn't it??? This is definitely extortion! I'm not asking.'
Lux immediately rejected the system's suggestion. He only had 10,000 resource points left, reserved just in case he needed to buy antiviral serum. He hadn't even been willing to pay for intelligence on high-level mutated zombies before, let alone spend 50,000 on some irrelevant commercial secret.
"Commander! Commander! What's wrong with you?!"
Lux felt his face being vigorously kneaded by a pair of small hands. When he looked up, HK416 looked like she was about to cry.
"Huh? What happened?"
"You suddenly started spacing out. I thought something had really gone wrong with your body."
HK416 asked worriedly.
"Yeah, Brother Lux, do you feel uncomfortable anywhere? If you say it early, we can think of solutions sooner. Worst case, we can try to catch a doctor and have them take a look at you."
Lianne asked calmly.
"Hahaha, nothing to worry about. I'm just hungry, and this new flesh growing back is really itchy."
"You two don't need to worry. Lianne, my body really has been modified. I injected something called a gene modification serum some time ago, so my wound healing speed increased. Don't worry, it doesn't affect my lifespan."
Lux said with a smile.
"Gene modification serum… that kind of thing really exists? I'd love to see it."
Lianne was a little surprised. As far as she knew, although countries were researching such technology, she had never heard of it being applied to humans.
"Maybe I can get one for you to look at in the future, but that thing causes a bit of mental pollution. Such a big syringe has to be injected directly into the heart."
Lux gestured to show the syringe's size.
"Huh? That big? If all of it is injected… wouldn't the heart explode?"
"I—I'm not sure. I didn't think about it back then. I just passed out after the injection."
Lux froze for a moment. His sanity had dropped to zero back then due to the huge needle and heart injection, so his memory of it was fuzzy.
"Interesting. I understand now. Brother Lux, your heart's pumping capacity has already been greatly strengthened. Otherwise, it would be impossible to disperse that much liquid throughout your body in one go. Injecting it through the heart to spread it across the entire body… truly a genius idea."
"Once pumping capacity increases, your oxygen delivery capability is also greatly enhanced. That's how you can maintain such terrifying speed."
"And abundant oxygen allows ATP in your body to constantly undergo oxidative reactions and release massive amounts of energy. I see now."
After thinking for a while, Lianne spoke with sudden realization.
"I didn't really understand most of that. ATP sounds familiar, but I only remember it has something to do with supplying energy to the body."
Lux pulled out a block of compressed rations from the system's storage space and started chewing on it viciously. He was starving, and nothing provided satiety and calories faster than compressed rations.
"Simply put, the drug you mentioned greatly improved your body's energy supply system. I was previously worried that with such high-intensity movement, your cells might rely heavily on anaerobic respiration, or even consume themselves for energy."
"But now it seems this gene modification technology is very mature. It fundamentally solves the problem of insufficient human energy output. You could say there's basically no long-term downside. The only issue is that after being injured, you might need to consume a large amount of food to replenish calories."
Lianne analyzed the principle behind Lux's strength.