3rd Persons Perspective
"I'm the one who taught Senku the formula! So please, Kill me. Not him"
Senku was shocked and angered at the same time. Yuzuriha's tears were cascading down her face. Tsukasa was just as shocked as the two people standing up.
'I jinxed it. Again.' She thought.
"Why did you tell him?!" Senku exclaimed.
"You're the one whos going to!" She stood up with tears in her eyes. "I'd rather die than have you get killed!" she quivered, then, forced a smile. "One scientist is enough."
"Do you think he's gonna let me off if you'd tell him?!"
Tsukasa let out a chuckle, catching everyone's attention. "Thank you, (Y/n). " He said. "However, I have no reason to kill you." He came off in a serious tone, letting Yuzuriha go, and coming towards her. "You're already dying."
"Let her go, Tsukasa." Senku stepped forward, ignoring what the said male said, not even wanting to believe him. "She has nothing to do with this. I did everything they just helped me."
"S-Senku . . ."
"Very well then, if I let you live," Tsukasa said. "You would let civilization develop. Will you promise that you wouldn't do that?"
Senku laughed. "What the hell are you talking about?" He said. "Why would I even keep a promise like---"
"No, you would never lie." Tsukasa Cut him off. "Not to science."
There was a brief moment of silence before he continued again.
"Will you promise here and now, for all eternity, that you'll abandon science?" His eyes softened. "If you do, won't have to kill you, Senku."
All of them held a surprised expression on their faces.
Then, Memories from where he first had a passion for science. From where he announced going into space during his first grade. The books he read as a kid, even dismantling his game console. To his father who sold his car just to buy materials for his experiments. His first experiment with a magnifying glass and a paper, how he cooked iron sand and aluminum foil almost melting the pan he was using, and the machine that he made, using liquid oxygen. Meeting the Oki siblings in primary school and meeting Yuzurhia in middle school. How he made spaceships until it worked and reached outer space.
Then, He decided. "You can accomplish anything through diligent application of science." He said.
'Ah, I really did something stupid, didn't I?'
"Senku, I'd rather not kill you if I can help it." Tsukasa said. "I'll ask again. will you promise me here and now that you'll abandon science?" He asked in a serious tone.
He paused for a moment, then, answered his question. "I can't do that." He confidently said.
"I thought that'd be your answer." Tsukasa smiled.
Senku chuckled. "What are you babbling about?" He asked. "You were going to kill me at some point even if someone helped me. No matter how I answered. "To be on the safe side."
Tsukasa paused for a moment before answering him. "Perhaps." He said.
He cracked his neck as if he was making a gesture. "Do it in one blow." He said. "Making me bleed out forever wouldn't be logical for either of us."
(Y/n) gasped, remembering something Senku told her the time they were alone in their journey.
"Listen, (Y/n), a small portion on the back of my neck is still petrified. Remember what I said when the revival fluid cured Yuzuriha's pain on her petrified toes?" Senku said as he got closer to her.
'The fluid reverses the effects of petrification and cracks get mended! He'll get healed!'
She is still shaken up about the fact that her crush and best friend would be put to death in front of her.
"Don't worry." Tsukasa said. "I'll bust your cervical nerve in one blow. You'll be knocked out unconscious instantly, and then, you'll die. I won't make you suffer. I promise not to miss."
"Taiju-Kun." Yuzuriha mumbled in hoped that Taiju could save them before Tsukasa could ever kill Senku.
"Senku, if we'd meet three thousand seven hundred years ago . . ." Tsukasa trailed off. "If we'd met before this planet became a stone world . . ." His face softened. Even hesitating to kill Senku. "You may have been my first friend."
Senku smiled back, not really expecting Tsukasa's sentimental words. "Maybe."
Yuzuriha spotted Taiju running at full speed while yelling Senku's name. Tsukasa's face went serious. (Y/n) was crying silently, already on her knees, watching the two with dilated eyes.
Tsukasa walked behind him, then, without hesitation, he broke his neck.
Yuzuriha ran to him in tears, Taiju yelled his name, and (Y/n) was there, breaking Senku's fall.
All of them, excluding the long-haired male was gathered around him. The head-phoned girl muffled her sobs. The older Oki was screaming the mad scientist's name with tears cascading from his eyes. The younger Oki was just sobbing, pulling his dead body, hugging him, crying on his shoulders.
"Senku!" Taiju yelled. "Answer me! Answer me, please! No, this is wrong, it can't be! You can't die here! There's no way!"
"He didn't suffer." Tsukasa said, with his head hung low, facing the opposite direction from where they were. "I suggest that, as his friends, you give him a proper farewell."
Tsukasa felt something. A cold chill ran up his spine. He turned around, looking at Taiju and (Y/n).
'As long as Yuzuriha could be used as a hostage, Taiju would never attack me.' Tsukasa thought. 'But Taiju, if Senku's death were to enrage you, and drive you to attack me mindlessly, I'd have to kill you, too.'
"Ne, Tsukassan." The female scientist called, getting the long-haired male's attention. "Why didn't you kill me?"
"There's no point killing a person if she's just going to die out of her own illness."
That's where everything went downhill. All her efforts to hide this illness of hers, acting tough, and going with the way of life. (Y/n) was already planning to sacrifice her life for the sake of civilization.
"You're sick?" Taiju asked. His face went paler than a ghost. Afraid of his sister's illness and what it's going to do to her. In the world they lived in, (Y/n) was the only family he had ever had. Their parents died when they were little, and they haven't seen any statues of their grandparents either.
"Not now, Onii-Chan." the girl sobbed.
Taiju stood up and walked towards a huge boulder, then, he pulled it, shocking everyone.
"Taiju-Kun!" Yuzuriha called him.
"Don't worry, Yuzuriha." He said. "I'm calm."
Tsukasa was already in a fighting stance.
For once, the strongest primate high schooler
Can't even let his guard down for one second.
'It seems I have no choice but to fight.'
"Sorry, Yuzuriha, li'l sis." He whispered to them. "If it comes to this . . ." He whispered something to them, then, Yuzuriha teared up.
"It's okay, Taiju-Kun." Yuzuriha smiled.
"The four of us made a promise." (Y/n) said, succeeding in trying to carry the supposedly dead body of Senku. "It'll work out, Onii-Chan."
"Yeah, It has to." Yuzuriha added.
Taiju's eyes were brimming with tears. "Yeah!" He said. "Thank you, Yuzuriha, (Y/n)."
With the help of his own force, he threw the boulder above Tsukasa.
His eyes widened. 'Why did he throw it in the air?' He looked at him. 'The boulder is a decoy.' He thought. 'Taiju, I can see you. No matter what you do you've lost.'
'He wouldn't dare take his eyes off of me.' Taiju thought. 'But, that's when I have my chance!'
Yuzuriha ran, getting the pot of black powder and threw the pot at Tsukasa as he kicks it, full force, breaking the earthenware into pieces.
'Black powder.' He thought.
'This is our ultimate weapon against Tsukassan.'
"The four of us made a promise to fight alongside each other!" Taiju shouted.
Yuzuriha went back towards the siblings' side.
"Goodbye, Tsukasa!" Taiju yelled as the rock collided with the black powder and ignited, creating a huge explosion.
The three of them ran deep into the forest with Senku's body, carried by (Y/n) through the help of adrenaline, the two were running with materials on their hands.
The weather changed. It rained.
"That's right, Senku. You said it yourself!" Taiju said while running. "If we need to run, we run together! I don't care what anyone says, I know you aren't dead!"
"Onii-Chan!" The girl carrying the body said, stopping under a tree. "Let's stop here!"
=================================
"Heart massage." Taiju said, pumping Senku's chest. "I don't even know if I'm doing it right, but I have to do it." then, he stopped and thought about something. "Artificial respiration!"
When Taiju was about to do CPR, Yuzuriha stopped him. "I think you should keep his neck still!"
(Y/n) coughed. not hiding the fact that she was sick anymore. She tried finding the revival formula while struggling to breathe.
"(Y/n)!" Taiju called, abandoning Senku's body. "Don't push yourself." He said, pulling her off of the bag they carried.
"Nital!" She coughed. "I need Nital! The revival fluid!" She cried, trying to escape Taiju's grip.
"Tsukasa-Kun hit Senku by his neck." Yuzuriha sobbed. "You saw it too, didn't you, (Y/n)?" She looked at the girl in front of her. "Senku-Kun sacrificed himself for us."
"No, he didn't!" She yelled. "Yuzu-Nee, Senku told me something that should be kept secret because of emergencies."
Taiju let go of her as she walked closer to Yuzuriha. "He took the risk of letting Tsukassan kill him, knowing that he could die." She said, letting out a few coughs while covering her mouth. "That's why, Yuzu-Nee, I need the Nital."
"His neck." Yuzuriha said, remembering Senku cracking it. "He's never done that before." She stated. "I think Senku-Kun was deliberately inviting Tsukasa-Kun to attack his neck."
Taiju carried Senku, holding him by the stomach, making his back facing them. There they saw, the small petrified part of his head.
"Here." (Y/n) said, giving them the small bottle of the revival fluid. "Pour this unto his neck."
The two remembered what the male scientist told them about a day ago and poured it unto his neck carefully. then, It was removed. The stone cracked, and the petrification was undone.
"Wake up! Senku!" Taiju yelled. "I know you won't die in a place like this!"