My brother is a demon king

Another member of the demon slayer corps approached Chikafusa and inquired about his distress. Through his sobs, Chikafusa managed to convey, "It's from Hajime-San. He wrote that he's... he's dead."

He tried to wipe away the tears cascading down his cheeks, but every attempt only seemed to bring forth more tears.

But the demon slayers weren't bothered by his death and showed little reaction. "Yamamoto, we know it's hard for you but it's a part of our corps. We always lose someone in this corps. Yesterday, we lost Oyakata-Sama. You shouldn't let your guard down—"

Chikafusa becomes furious and his tone turns serious, "Do you even know what you are saying? He is the most important person in our corps. He always trained all of us and helped in reviving the corps again. Oyakata-Sama always felt gratitude towards him and wanted to meet Hajime-San for the last time. He is the only one who can defeat Muzan Kibutsuji!!! HOW CAN YOU SAY SUCH THING ABOUT HIM??!!!"

Everyone stays silent in response to Chikafusa. They accepted their faults.

Chikafusa returns to the corps' hideout, his friends are waiting for his arrival. With a gloomy face, he confronts them.

"Yamamoto-Kun, you've finally arrived. I'm glad about it. But where is Hajime-San?" said the girl with pink curly hair.

Chikafusa stays silent...

"So you've found out where did that brat go?" asks Tsunenari.

"Yoshimitsu-san, don't cross your line. Just call him Hajime, alright?" says Ai. "Yamamoto-Kun, what's the matter? Didn't you find Hajime-Kun?"

Without meeting her gaze, Chikafusa speaks with a heavy heart, "I apologize for the trouble, but…"

"But…? Spit it out. You're giving me bad vibes, ya know? If you haven't found him then it's okay," says Ai.

Chikafusa's voice grows more grave, and he chokes back tears, "Hajime-San… He's… He's no longer with us. Hajime-San... is dead!"

A wave of shock crashed over everyone as they processed Chikafusa's words. Shock and disbelief clouded their faces, and while they couldn't bring themselves to accept it, they could see from Chikafusa's expression that he was serious.

Ai's world seemed to shatter with the news. Her eyes widened in horror, and her voice cracked as she lashed out at Chikafusa, "B... Baka... No... Do you even know what you are saying? How can you be… so sure? Did you… see him?.. Are you...". Her words trailed off, overcome by raw emotion as tears brimmed in her eyes.

Unable to contain her grief, she turned and fled to find a place to hide her tears.

She reaches the butterfly mansion and isolates herself in her room. Her face is filled with tears and her mascara has been spread over her cheeks. Her face turns red and she hides her face in her knees.

"Ya must be kiddin'. Why would you say so? Are you completely sure that he's dead...? Don't make me feel vomit..."

...

"After a long time, I found something like a family. I can never forget mama and papa, but it's also true that I think of y'all as my family. But still, I don't know why did I feel so overwhelmed when I heard that Hajime-Kun was dead. I know that he's my best friend, but that doesn't make any sense. I always put logic above emotions, yet overwhelmed by the emotions just for him. Why?! Tell me, Hajime-Kun... Why?!"

The door slowly opens and Chikafusa arrives in the room. With deep concern etched on his face, he makes his way towards her in the room. "Hanako-San, I know it's hard to accept that Hajime-San is gone now. I know that you liked him."

When Ai looked up at his face, she stopped weeping, "Why... Why do you think so?"

"I know that you liked him. You always act unnatural when you're with him. Your concern for him has grown even more in these past few years. Your aura smells different when you're with him."

Ai holds back her tears and says in a sad tone, "I hate to accept it, but you're right. I have developed a damn crush on him in these few years. I envied him so much, but as time went by, my jealousy eventually turned into love and concern. As I heard the news of his death, my world completely twisted right before my eyes. But how do you exactly know that he's dead?"

Chikafusa's hands tremble as he hands her the final note from Ren. "It's the note that he wrote and gave it to his crow. But his crow was found dead with this note."

Ai carefully reads the words on the note, "I am likely dead? Why would he say so? This is undoubtedly his writing, but why? There may be some chances for him to be alive, but what about his crow? Where is he now?"

...

Tears streamed down her face again and she started crying loudly.

———————————————————————

At night.

Near a lake, a kid is fighting several demons at the same time.

With deep focus, he synchronized his breath with his movements as he lunged at the demons. In one swift and effortless motion, he decapitated each of them with a single powerful swing of his weapon.

"Ugh... That was quite hard."

.

Ren slowly approaches the boy and says, "You've improved a lot in just one day. It takes some months to achieve this level of perfection."

"When I said that I'll eradicate every single demon from this existence, I wasn't joking around. I am desperate to kill them mercilessly."

Ren softly smiles. "So you won't let me kill even a single demon, Kasumi?"

The boy's name is Kasumi Matsunaga.

"No, I won't let you kill any demon as long as I am here. Just sit back, train, and watch me."

Ren softly giggles.

"You look so mysterious. Even if we met yesterday, it feels like I've seen you before," says Kasumi.

"Why?"

"Right before meeting you, a person used to appear in my dreams. I wondered who he could be. He appeared so many times that his image has been saved in my mind. But since you entered my life, he stopped appearing in my dreams. He has the same earrings as you have, and he looks almost the same as you. I've even seen my past lives, and I won't ignore them like nothing. Tell me exactly who you are?"

Ren's smile suddenly faded as he heard Kasumi's words. He becomes serious and his tone changes, "So you've been dreaming about your past life for a long time? And you've seen me multiple times? I don't know what you are talking about but I can only tell you one thing."

Kasumi listens to his words carefully, "And what is it?"

"I am finding my brother, the current demon king."

Kasumi's eyes widened in horror, and his face drained of color. "What?.. Your brother is the demon king? I can sense that you're serious, but how's this even possible?"

"I apologize but I can't tell you. The only thing I can tell you is that the progenitor of all the demons, the original demon king, the first demon to ever exist, is Muzan Kibutsuji. He will appear soon, but for now, the current demon king is even stronger than the original one. And my brother is the current demon king. I can't elaborate you further about this but everything I said is true."

"B... But how do you know so much about it?" His heart raced even faster than before, thumping loudly in his chest. He struggled to comprehend the words he had just heard.

"I know that it's like a fantasy to you. But trust me, everything about your dreams, your past lives, and what I mentioned are true."

Ren vividly recounts the details of his previous life in the Sengoku Era, sharing stories of encountering demons, facing off against Kokushibo, and more.

The 9-year-old child finds it incredibly difficult to process this information and is utterly bewildered by what he has just heard.

...

"So Muzan is the cause of all these causes? I swear to kill him. But why doesn't he appear right now?"

"I exactly don't know."

Kasumi smirks, "Is he afraid of you?"

"Ironically, yes," Ren laughs.

As the night begins to give way, the first light of dawn starts to appear on the horizon, casting away the darkness and bringing a new day.

Kasumi returns the sword to Ren and smiles, "Thank you for training me. The morning is about to come. But there's something I wanna ask you."

"Ask me what? Sure, you can."

"Why did you leave your place and choose to live with me instead?"

Ren's eyes widened again, nonetheless, he answered, "Demons were chasing after me. For the past few years, I've been observing them coming closer and closer to the corps. And 3 days ago, they almost found the corps. I didn't want anyone to die, so I left the corps. I've decided to not come back until I defeat Muzan Kibutsuji. Now demons are after us, but I can handle them now. And when I saw you, I couldn't help myself but help you. I know that it's too hard for someone at your age to live without anyone."

"But what about your friends? Don't you miss them?"

"Of course, I do. It's so painful and heart-wrenching that I can never move on from that."

Kasumi looks at Ren's eyes which are filled with sorrow. He can clearly see that Ren is hiding his feelings.

"I can sense that he's overwhelmed by emotions. My sorrow level is 768 while his level is 89,013. My sorrow is nothing compared to him," thinks Kasumi.

Before he could even react, Ren interrupted the silence and said in a calm voice, "Matsunaga-Kun, from what I've observed your swordsmanship skills, I can teach you a breathing style. A breathing technique that suits your fighting style."

Kasumi immediately looks at him in surprise and says, "Huh?! A breathing style for me?"

"Yes, a breathing style for you. You mostly focus on your movements and agility. There is a breathing style that I can teach you."

Kasumi says in surprise, "What's that?"

...

"Breath of the mist."