Demon Slayer: Kimetsu no Yaiba: Hinokami Flames

Prelude: Flamboyant Sound Training

A month has passed ever since Kanae was put in a coma with no signs of waking up. It has affected the Butterfly Estate much. Shinobu stated to smile in order to fill the void left in her heart. Aoi became very stricter with the demon slayers in recovery. Kanao was unaffected by it. And Zenitsu began training ruthlessly in order to get stronger, so he won't lose anyone else.

The following night, Zenitsu was speaking to Shinobu. "Was it ever possible to learn a second Breathing Style?" he asked.

"Oh!" Shinobu was surprised by the question. "To be honest, it's never been heard of mastering two Breathing Styles before."

"I was just thinking of ways to stop the demons. Kanae was defeated by a Twelve Kizuki, and I figure using two styles at once would be a massive advantage."

"The next Hashira meeting is tomorrow. I could inform the Oyakata about your idea, and let's hope the other Hashira will approve of it."

"Thank you very much Shinobu!"

Shinobu patted her brother's head in comfort. "I will always support you Zenitsu. Now how about you go get some sleep? You've been training all day."

"Of course. Good night."

"Good night."

(The next day)

Zenitsu and Kanao were sparring as Aoi, and the butterfly girls watch. Taking a break, Zenitsu has lunch by himself. But he begins to feel someone watching him. He looks around not seeing anyone. "It's probably just my imagination."

"Blond hair?" Zenitsu was snapped out of his thoughts and looked up to see a man close to his head. "You look flashy, but you don't fight flashy." Zenitsu jumped because the man appearing before him didn't even make a sound. "What? You're telling me never saw a shinobi before? You are oblivious." 

"Shinobi?"

"That's right. I'm a 'former' shinobi. My name's Tengen Uzui, the Sound Hashira. For some reason, I hear about how someone training to be a demon slayer says something about mastering two breathing styles."

"You have?"

"Yeah." His scowl turns into a smile. "And I think it's very flashy."

"Huh?"

"It could be a very good idea for the demon slayer corps. I suppose you could try and learn it since it's your idea."

"I'm sorry, huh?!"

"My Sound Breathing Style originated from Thunder Breathing, something that you already mastered."

"I think what Tengen is trying to say is that he wants to train you in Sound Breathing." Shinobu said entering the dining area."

"Shinobu." Zenitsu muttered.

"The Oyakata approved of your idea, but only if you were the first to perform it."

Tengen then spoke once again. "I purposely volunteered to train you in my Sound Breathing. You will be spending this next year training in my styles. And then you'll return here for your Final Selection. I'll ensure you become a flashy demon slayer like myself." Tengen wasted no time grabbing Zenitsu leaving the estate at such haste. Shinobu told Kanao about their brother's situation, and it cause Kanao to lean back to using her coin to decide.

(Uzui Residence)

"Welcome to your home for the next year." Tengen said. "You will be learning everything that I know. Every day before sundown, you will spar with me, and when you achieve victory, I will allow you to go home. You will obey every instruction, you will respect my authority! For I AM GOD!!"