Douglas then began working on the specialized serums for the entire Strawhat Pirates, carefully using their blood as the primary genetic material to ensure that each serum was engineered and tailored specifically for the intended Strawhat member. He conducted multiple cycles of readjusting the formula, cultivating and growing specialized cultures, and synthesizing RNA strands to guarantee that the effects would be not only potent but also completely permanent.
Eventually, Douglas finished the unique serum doses for each of the Strawhat Pirates. However, one particular blood sample caught his attention—Sanji's. The sample contained traces of genetic rewriting, remnants of modifications Judge had administered in the past. Sanji's genetic code also carried an inactive mutation, presumably similar to those of his siblings, but one that had been suppressed and stopped by his mother before it could fully manifest. Seeing the potential implications, Douglas decided to inform Sanji directly of his discovery.
"Did you know about this?" Douglas asked, even though the answer was already obvious to him.
"Yes," Sanji replied with a steady voice. "But I was considered a failure. My abilities never awakened. Doesn't matter—I've already left that past behind me."
"It's not erased, only dormant," Douglas clarified. "It would gradually awaken if given the right catalyst—like my serum. The serum works by repairing genes to their most perfect and optimal state, which in turn would trigger your mutation to begin activating."
Sanji froze at those words. He had long since left that part of his life behind, and from what he knew, his siblings were incapable of feeling emotions—something he valued deeply and had no desire to lose.
"I don't want those modifications to awaken," Sanji said firmly. "I know exactly what would happen. It would turn me into a cold, emotionless monster. So please—don't inject me with the serum you've created."
"Relax," Douglas reassured. "The serum has already corrected your genetic code. It will only cause your latent abilities to awaken gradually, and without the negative emotional side effects. It will just take a longer time than it otherwise would."
Sanji allowed a brief, small smile to cross his face, but his expression quickly turned serious once again. "Douglas, can I ask you something?"
Douglas, already predicting what Sanji was about to request, answered without hesitation. "No, I will not make you an invisibility suit."
Sanji collapsed to his knees, tears gathering in his eyes. "Please!!! Imagine the good I could do with that suit—I could help the world… peep in the women's bath, or save someone… peep in the women's bath, or simply… peep in the women's bath!" His face remained serious, but his nose had already begun bleeding heavily.
Douglas, without another word, physically threw Sanji out of his makeshift laboratory—converted from the cannon room at the front of the Going Merry. Sanji, however, immediately began begging again from outside. The other Strawhats looked on knowingly, fully aware of what Sanji had been asking from Douglas.
Turning back to his work, Douglas enlisted Chopper's help once more to administer the serums. The process required injecting the serum directly into the bone marrow via the spine, a procedure that could be extremely painful for anyone unaccustomed to such intense sensations. Luffy was the first volunteer. To make the process easier, Douglas temporarily canceled Luffy's Devil Fruit abilities using his own, while Chopper administered the injection. Luffy instantly screamed in pain, startling Nami and Usopp so much that they turned away in fear.
"What was that, Douglas?!" Luffy demanded, clutching his back.
"Don't worry," Douglas said calmly. "It's painful for a moment, but it won't cause any harm. Here—have a lollipop. You were a great patient."
The moment Luffy saw the oversized lollipop, the pain vanished from his mind, replaced by childlike delight. He skipped out of the lab happily, munching away.
"Oi, Luffy, what happened in there?" Usopp and Nami asked at once, both visibly tense.
"Oh, Douglas had this giant needle and stuck it right into my back. Hurt like crazy for a second, then it was gone like magic, so no big deal," Luffy replied cheerfully.
That only made Nami and Usopp even more terrified. At that moment, Douglas emerged from the lab, spotting their fear and immediately getting an idea.
"Nami, Usopp—your turn," Douglas said.
Both froze, slowly turning toward him. They tried to insist that others should go first, but Douglas refused, stating their serums were already prepared in the injections. When their stalling continued, Douglas lost patience and used his Devil Fruit power to pull them into the lab against their will. Both squeezed their eyes shut and cried out in fear.
To their surprise, they felt nothing.
"Hahahaha! Of course there's anesthesia for this," Douglas said with a smirk. "I knew you two were wimps."
Nami and Usopp began crying and loudly complaining, while Douglas and Chopper laughed openly at them. The remaining crew members were then injected one by one. Robin accepted anesthesia without protest. Chopper was offered the same but refused, declaring he wanted to "become a real man" and get used to pain—only to immediately regret his decision when he screamed just like Luffy, earning a lollipop from Douglas.
Zoro, Sanji, and Douglas himself took their injections without anesthesia. Zoro and Sanji amused themselves by teasing each other over who would yell first. Douglas, however, wanted to fully experience the procedure he had subjected the others to. Unfortunately for him, the pain he endured—even without using the Dark-Dark Fruit—was ten times worse than anything the others had felt. Still, not a single sound escaped his lips, not even the faintest wail.
Days passed without incident. The crew didn't notice any immediate changes in their bodies, so they simply continued with their usual routines. During one of his training sessions, Zoro paused and looked at his hands. Something felt different—his training didn't seem to be working the same way anymore. He wasn't even getting tired, and strangely enough, every movement felt like he was carrying something far heavier than before, yet without strain. Curious and slightly concerned, Zoro went to consult Douglas.
"Oh, that's nothing to worry about," Douglas explained calmly. "You've actually become drastically stronger in just the few days since I administered the serum. Don't you know that muscle strength comes from repeatedly breaking down the muscle fibers and then letting them heal? Well, now your healing is so fast that your muscles have been strengthening at an accelerated rate without you even realizing it. You've been breaking them down and repairing them so efficiently that you've skipped the feeling of fatigue entirely. Trust me—just keep following your normal training routine. The whole crew will get stronger without even noticing it happening."
Hearing this, Zoro smirked at Douglas—a silent, confident acknowledgment that this was exactly the kind of outcome he had been hoping for. But Zoro wasn't the only one starting to notice subtle changes. Nami, during one of her morning routines, realized that her skin felt softer and smoother than ever before, almost like that of a newborn, the kind of flawless texture that even expensive cosmetics couldn't replicate. Usopp, whose eyesight had always been exceptional, suddenly found that it had become so sharp and precise it was almost unnatural—he could spot details at great distances as if looking through a finely tuned telescope.
Sanji, meanwhile, was quietly noticing changes of his own. His body felt lighter yet far more powerful, his kicks carrying more force than before without any additional effort. The strength in his legs and the resilience in his frame seemed to grow with each passing day, and though he didn't say it out loud, he was well aware that this was no ordinary improvement.