After Tengen explained the plan, everyone was getting ready. As he was putting makeup on the boys, Xenovia walked up behind him. "Hey Tengen, can I ask you something?" she asked him. "I don't want to have a kid with you, I'm taken by three girls you know" Tengen told her. "No it's not that, I want to know how Rengoku became a Hashira."
"Ask Rias, she was there" Tengen told her. "Huh?" everyone said. "What are you talking about?" Rias asked him. "Remember, you and your brother went to the Hashira headquarters two years ago. You guys attended the Hashira meeting that Rengoku made his first appearance."
"I don't remember this" Rias told him. Tengen sigh and put down the makeup tools. "Don't look at a mirror" he told to Issei who's face was covered in makeup. "Why? Is is that bad!?" Issei said. Tengen turn to the others and said "Before Rengoku became a Hashira, he was training Mitsuri to become a demon slayer-"
Flashback
Tengen and the other Hashiras came to the Hashira headquarters to attend the Hashira meeting. The only Hashira there at the time were him, Gyomei, Sanemi, Giyu, and Shinobu. On the side was a boy who look like Shinjuro Rengoku. "It's been half a year my adorable swordsmen, how have you all been doing?" Oyakata asked them. "Fine!" everyone reasponded at the same time.
"Things have gotten a lot more lonely since before, Muzan's strength is still growing as well. Forgive me for this, but I will be sending you all out on more missions in due time. I want you all to support each other and strive to achieve your duties more than before."
"Understood, by the way Oyakata, why is there a non pillar swordsman here? What happen to the flame pillar Shinjuro Rengoku?" Sanemi said, referring to the blond hair boy. Something that the Hashiras didn't know was that behind Oyakata were devils, also known as members of the Gremory family. Sirzechs wanted to meet Oyakata and decided to bring Rias along. Right now they were spectating the meeting, and they turn to see the blond boy sitting on the side.
"Father is-"
"Hey! Are you really fit to be a pillar stand in?" Sanemi asked the boy. The boy shivered and Oyakata said "Sanemi, don't pick on him too much. I called Kyojuro over so he can explain what happen."
"You must all be worried about Shinjuro, can you tell us how he's doing in his home?" Oyakata said. "I have no proof of this, but ever since my mother passed away, Shinjuro has lost all his will to fight. He has started drinking while on duty, and he is currently shutting himself inside his room drunk" Kyojuro said.
"What an absolute shame, Shinjuro has served the pillars for a long time. But we're all in a position where we must stand together" Gyomei said. "He's also setting a bad example for our fighters. It's plainly affecting out morale, I suggest a flamboyant retirement" Tengen said. "We don't have enough pillars, but a drunkard won't be of any use to Oyakata either, so what do we do?" Sanemi said.
"That won't be an issue! If I become the flame pillar, then I'm sure my father will regain his motivation!" Rengoku said, raising his voice. Tengen chuckled and Sanemi said "Woah Kyojuro Rengoku, you sure have a lot of confidence. Being a pillar's not as sweet as you're recklessly proclaiming to be."
"Of course I know the promotion requirements of being a pillar!" Rengoku said. "Then show me your skills bitch" Sanemi said, standing up. "Sanemi" Gyomei said. "Gyomei please, and forgive me Oyakata" Sanemi said, as he rush at Rengoku. He swung a kick to his head and started swinging at him. "Sanemi!" all the pillars shouted.
"Be a pillar already! Start running around and finding demons! We have open pillar seats here, when will you get here? When will you sit here? Get right fucking to it you fucking dumbass!" Sanemi shouted. "Now come on! Hit me back, why don't ya?"
Rengoku blocked his elbow and shouted "I would never hit you! Swordsmen are forbidden to fight among one another! And I would never hit a human being!"
Sanemi stood there shock and Rengoku said "Plus I don't wanna hurt you either! I see you're a seriously guy, but you have a burning passion within you! Thanks for what you say, I'll do my best!"
"D-Don't thank the guy who's trying to punch your brains out!" Sanemi shouted at him. 'He's a weirdo" Shinobu said in his head. 'He withstood Sanemi's attacks, and he got flamboyant hair. I like this guy' Tengen said in his head. "Sanemi" Oyakata said. Sanemi bowed down and said "Please forgive me, I got a bit too heated there."
"Ok, Kyojuro, I'm sure you already know the conditions to become a pillar. We actually have information about a demon near the capital, and there's a high possibility of it being one of the twelve moons. I'd like to entrust you with extermination of this demon." The pillars were shock to hear this. "Forgive me for saying this Oyakata, but if this is actually one of the twelve moons, we should be the ones going out" Shinobu said.
"I can't give you a mission that is outside your designated patrol regions, besides this is taking place in Shinjuro's region" Oyakata said, making Rengoku shivered. "If you say you can become a pillar, don't just tell me but show me. Then I and everyone else will accept you. Show me your true power, Kyojuro."
"Understood!" Rengoku shouted. He then started leaving and Gyomei asked "Oyakata, can you see a future where he defeats one of the twelve moons or is it just intuition?"
"Not really intuition, but actually something more akin to confident confirmation. Kyojuro Rengoku, will change the destiny of the demon slayers in the future."
End of Flashback
"That's what happen" Tengen said. "I knew I recognize that hair from somewhere" Rias said. "Wait, did you say he went to the capital to kill the demon?" Xenovia asked. "Yeah why?" Tengen asked. "Because I was sent to a mission from the church to stop this creature that was exploding buildings there. And I think I did run into Rengoku while I was there."
Flashback again
Mitsuri was trying to get rid of the bombs that were set by the demon that Rengoku was fighting. She was having trouble since weird dogs appear and started biting into her arms. As she was having a difficult dealing with them, someone sliced one of them. The girl was wearing a white robe and had blue hair.
"Thank you, are you a demon slayer as well?" Mitsuri asked her but did not get a respond back. "You can call us that" said another person. She turn to see a girl with caramel hair walking up to them. "Xenovia, I told you to wait before attacking" the girl told the blue hair girl. "I'm sorry, I was trying to get this done fast" Xenovia said.
"I'm Irina, and this is Xenovia" the caramel girl said. "I'm Mitsuri, can you guys help me deal with these bombs. My teammate is fighting a demon right now."
"Where is it?" Xenovia asked. "What?" Mitsuri said, as they then heard gun shots. Xenovia started running over there as Irina was calling for her to come back. She saw a wolf like monster fighting a blond hair man.
A/N: This is what he looks like
She jump into the air and was about to swung her sword down before she the demon caught her by the neck. "Who is this now!? Another demon slayer!? Are you a friend of Kyojuro Rengoku!?" he shouted as he was chocking her. He then put his sword to her neck and shouted "If you get near me, I'll slit her throat!"
Rengoku stood there confuse on who the girl was and where she came from. But he knew he had to go and save her. He dash at the demon and slice off his arm that was holding her. He then slice the other one and was able to grab her. He ran before the demon got the time to hit him back. "Are you ok?" Rengoku asked her.
She nodded her head and Rengoku said "Good, now stay here!"
He rushed at the demon and their swords hit each other. Rengoku was having a difficult time but he then shouted "Flame Breathing Ninth Form: Rengoku!"
He was able to slice the demon's neck off and he collapse. Xenovia ran over to him and said "Hey, are you ok?"
Mitsuri and the others ran to them and she said "You did it Rengoku! You beat one of the twelve moons! You can now be a pillar!"
Rengoku was just staring into the sky, trying to catch his breath.
End of Flashback
"So he did beat one of the twelve moons, but it was a lower one" Issei said. "Thinking about it now, it makes me seem like a fool when I got to meet him again. I should've thanked him for saving me" Xenovia said. She sigh and said "I need to go get some air."
She left and went outside of the house. She stare at the landscape around them and the wind started blowing, making some of the petals on the ground lift into the air. They cover her view but when they calm down, she was shock to see who was in front of her.
"Rengoku!" she said. All he did was smile at her and she said "Thank you for saving me that day, I wish I hadn't say it like this. Also, remember I still love you." The wind started blowing again and the petals were going into the air, covering her view again. When the wind clam down, Rengoku was gone. Xenovia smile and went back inside.
A/N: Hello, so this chapter was based on the Rengoku manga spin off that tells how he became a pillar. I wanted to include this into the story and I thought this was the best way to do it. I hope you guys like it.