Tamayo's fingers tightened around the glass vial until her knuckles turned white. The blood inside felt like it was burning her skin.
Longevity drug?
That was exactly what Muzan had been chasing for a thousand years. The same obsession that had created every tragedy she had ever known.
She stared at Shuya, eyes hard. A drug that removed the fear of sunlight, removed the need to eat human flesh, and granted eternal life while letting them live like normal people. If she helped create that, she would be making something even more dangerous than Muzan.
She lifted her chin. "Kill me if you want. I won't make the drug you're asking for."
Yushiro's face went pale. "Lady Tamayo?!"
He had spent his life as a demon because she gave him one. To him, what Shuya wanted didn't sound that different from what she had already done for him. But Tamayo shook her head and refused to explain.
She knew the difference. Yushiro was hers to control. Shuya was not. If he gained that kind of power and centuries to develop it, combined with his ability to steal Blood Demon Arts, the result would be far worse than Muzan.
Yushiro stepped in front of her anyway. "Then I'll hold him off. Lady Tamayo, please run."
Shizuka blinked, completely lost. "Wait… did Shuya even say he was going to kill you?"
She didn't know the full story of this world. To her, wanting to live forever with the person you loved seemed normal. Especially when they had Greed Island connecting multiple worlds and access to things far stranger than demons. They could probably figure out longevity on their own eventually. They just wanted to speed things up.
Shuya spoke calmly. "My ability is called Equivalent Exchange. The key word is 'equivalent.' If you refuse, I can't force it on you. And even if you say no, I have no reason to kill you. Shizuka's medical knowledge is already close to yours. I came to you to make the process faster, not because you're the only option."
Tamayo looked at Shizuka, then back at Shuya. She took a slow breath and forced herself to think clearly.
The first request — a drug to turn demons back into humans — was already her goal. He had even given her Muzan's blood to help.
The second request was trickier, but not impossible. She and Yushiro had already mostly removed the need to eat human flesh. They survived on small amounts of blood. Turning that into normal food was just one more step. The real problem was sunlight immunity. Without the Blue Spider Lily, she had no idea how to do it.
Then Shuya dropped the final piece.
"I've already found the Blue Spider Lily."
Tamayo's mind went blank. For a second she thought she had misheard. Muzan had searched for a thousand years and found nothing. This man had it?
Shuya didn't even look smug. "It only blooms during the hottest part of the year, at noon, under direct sunlight. That's why he never found it."
Tamayo let out a short, bitter laugh that quickly turned into something closer to a sob. The irony was too much. All those demons, all that suffering, and the answer had been hiding in plain sight the entire time.
Shuya added one more detail. "It grows near the grave of Yoriichi Tsugikuni's wife."
Tamayo actually laughed out loud this time, tears forming at the corners of her eyes. The thought of telling Muzan the truth right before he died filled her with vicious satisfaction.
She wiped her eyes and looked at Shuya, voice steady. "I accept the deal. But I have one condition."
"When you kill Muzan, tell him the truth about the Blue Spider Lily. I want him to die knowing he spent a thousand years chasing something that was always right in front of him."
Shuya nodded without hesitation. "Done."
He manifested the glowing parchment of Equivalent Exchange and held it out to her.