A Cook, A Doctor, A Ghost and A Ronin.

Puzzle Box

Accompanied by Zoro and Tanjiro, Kotetsu approached the mechanical doll. He take out a key from his pocket and inserted it in the back of the head of the mechanical doll. As they key is inserted, the doll stood up and raised all of the swords that its been holding onto.

"Look here." Kotetsu tells Tanjiro to get closer. 

"I never told anyone about this, but if you turn the key on the back of the doll's head, you can change its movements." Kotetsu stated as he turn the key inside the doll's head. This is the first time Kotetsu had shared this secret with Tanjiro and Zoro.

"Have you ever seen a yosegi-zaiku puzzle box?" Kotetsu showed him a small wooden puzzle box. How are they were made? Different color woods are combined and bound. When these are thinly sliced, a patterned piece is completed.

"Yes. I know what it is. My little sister Hanako had one." The puzzle box takes him back to the days where everything is fine. When his family is still alive.

"It won't open unless you move it the right way. It's just like that." Kotetsu explained how the puzzle box works.  It's estimated there are approximately 60 basic patterns, and the way they are combined results in an infinite array of designs.

"Well, I'm not familiar with that. Achoo! I'm not into puzzles and everything." Since puzzle requires quite the thinking, Zoro do not like puzzles. They are simply annoying to solve and he prefers to solve everything with brute force. Like an idiot.

"In the case of this doll however, you can set its actions by the number of times you turn the wrists and fingers. The swordsmiths designed it with movements to exploit the weaknesses of swordsmen." Kotetsu turned the fingers couple of times while explaining about the doll furthermore.

"Otherwise, there'd be no point in using it for combat training." Kotetsu continued. This doll is created simply to find any loopholes in a swordsman's technique. It is designed to push the user to their own limits.

"Even without training to resist torture, I'd die before I told that to anyone I hated! Hehehehe!" Kotetsu lets out an evil laugh. The mechanism of the doll is only effective with input from its owner. Even if Muichiro got the key from Kotetsu, he won't be able to use it in its full potential.

"Now, the only thing that we need to do is start this." Kotetsu wanted to activate the mechanical doll, but his hands are trembling. Tanjiro noticed this. The kid is still scared and worried for the doll as it might break.

"You're still worried about the doll, kiddo?" Zoro asked Kotetsu. Kotetsu didn't answer. That means its true. Kotetsu sat on the ground, hugging his knees.

"Don't worry, I'll help with the doll if there's anything I can do! You can't give up! Your future is still bright!" Tanjiro volunteered to help with the doll if anything happened. He didn't want to see this young boy gave up yet.

"No, I won't! I know myself! I'm just no good! It will all end with my generation and it's my fault!" Tears could be seen running down behind the mask. Kotetsu blamed that he'll be the end of his father's legacy and blame himself for being useless.

*Bonk!*

"Yeow!!" A clean hit straight on Kotetsu's head by Zoro. He's getting tired by this kid whining like a little bitch. Kotetsu yearns in pain as large bump appeared on his head.

"Stop talking like it's the end of the world. It makes me sick. You can't abandon your responsibility." Zoro found it sickening and wants to vomit seeing how easily the kid wanted to give up after everything that had happened.

"You haven't even tried yet. So what if you weren't talented as others in swords or mechanical shit? You never tried and you will never know the results of the future!" Zoro continued his speech.

"You don't need a talent! Even geniuses will struggles between a rock and a hard place! Hard work beats talent and nothing else! If you wanted to be what you wanted to be then start from right now!" Tanjiro had to admit that Zoro is a bit harsh, but his advices were on point.

"Even if you can't do it yourself, you'll find someone else to carry on for you. You have to put in the effort for what comes next." Tanjiro tapped the boy in the shoulder.

"Even if you can never do it, maybe your children or grand-children will be able to, right?" Tanjiro talks about that even if he can't do it, someone will carry on his will to fix the broken doll.

"I want to defeat Kibutsuji Muzan and help my little sister who was turned into a demon. But I may die before I accomplish anything." Tanjiro revealed his intention to defeat Muzan and turned his sister back to human. He might die on this mission, but that's a price he's willing to pay.

"Still, I believe that someone will ultimately get it done. As surely as someone saved out lives and we went on to defeat an Upper Rank demon. The lives we save are certain to eventually defeat Muzan." Tanjiro knew even if he die, others will embark on the same path as him.

"Let's work hard together!" Tanjiro gripped Kotetsu's hand tightly. His speech inspired Kotetsu to not ever give up while also make Zoro sick. I'm gonna puke. This is disgusting and uncomfortable!

"Okay!" Kotetsu stated that he won't give up while still sobbong.

"I hoped the doll would never break, but I'm determined. Combat training should last until dark, so I'll get ready to see this to end like I should." Tanjiro smiled, seeing the boy started to have his spirit comes alive. 

"Are you guys still didn't finish yet? Hurry up, its about damn time." Zoro is uncomfortable with them and told Kotetsu to hurry up and activate the doll.

*Ka-Chak!*

*Whirr*

*Klak*

The doll's gear could be heard as it took a stance, ready with all of its six arms holding katana.

"Yeah! It's still works, Kotetsu! Great!" Tanjiro shouted happily as the doll is still working fine after 300 years. He's happy for the little boy.

"Yes! Train with this, Tanjiro! And get stronger than that emotionless jerk!! I will help you with all my strength!!" Veins could be seen pulsing under his mask. Tanjiro is a bit shocked at Kotetsu's sudden change of demeanor.