Ashen Demon

16

 Upon returning to the headquarters, those who were injured during the Mugen Train mission are sent to the Butterfly Estate. The only ones were Tanjiro and Kyojuro, who suffered much more brutal injuries than the teen since he fought against Akaza. He indeed fought with honor, with his duty as a Hashira to defend the passengers and the slayers working with him even if the situation isn't taking in his favor.

Looking back, had Byleth not intervened in time, the Flame Hashira wouldn't have survived the ordeal as it seems he was not strong enough to overwhelm the Upper Moon 3.

Byleth had planned to give Kyojuro some vulnerary to heal up his injuries, even though it wouldn't heal up his broken bones. That, or using her healing magic so he wouldn't have to go to the estate of the Insect Hashira. 

But she had ran out of vulnerary when she ended up giving it to Tanjiro since Kyojuro kept refusing to take it and wanted her to give it to him instead, and the bones had to be healed up on its own as using Mend could basically mess up the process.

Word circulated that Byleth had not only defeated not one Upper Moon, but two of them. They knew that it was Akaza that she fended off, but what they didn't expect to hear is that she also fended off Upper Moon 1, who is known as Kokushibo. Though, she told them she and Douma tag-teamed against him after letting the silver-haired Upper Moon fight him for a little.

"Are you fucking kidding me?! You let BOTH of them go?!"

Of course, Sanemi was not happy to hear that even though Byleth fought Akaza and Kokushibo, she did not kill them. She instead let them go. Obanai was also not delight about it, while the others were puzzled about it.

"I did with Upper Moon 1, but Upper Moon 3 left abruptly before I even realized it." Byleth remarks while sitting down with the rest of the Hashiras present in the private meeting with Kagaya.

"Why the hell did you spare Upper Moon 1?" Obanai questioned with irritation in his tone.

"To piss him off. It's humiliating for him to not only get beat up by a low-ranked slayer, but also a slayer that doesn't know a Breath." the mint-haired woman responds nonchalantly.

"I mean, when you put it that way... that does sound humiliating!" Tengen snickered behind his hand.

After all, Upper Moon 1 has been around much longer than the rest of the Upper Moons and had killed millions of lives. Hashiras and slayers in the past were never able to survive against him for he was too powerful. It's only expected since he is close to the demon king in terms of power realm.

It would be utterly humiliating for Kokushibo to be bested by a slayer that is not only low-ranked, but also not knowing a Breath. Even though in Byleth's case, she made up for it with the usage of her own magic which gave her an upper hand. That is, depending on what spells she uses.

"You mentioned that Upper Moon 1 is a former demon slayer. What Breath does he use?" Gyomei then asked the incarnate of the Fell Star. This made her appear thoughtful for a moment, digging into her memory to recall.

"I believe it was Moon Breathing." Byleth answered.

"Oh, it sounds pretty!" Mitsuri comments with a smile.

"Moon Breathing. I do not believe there is not a single one who has wielded that Breathing Style before from what I've known, aside from its cultivator." Kagaya mentioned with a faint smile on his face. Though if Byleth had to be honest, it seemed like he knows fully well that Kokushibo is the one behind its creation.

It's the bill that fits perfectly, given that Kokushibo is hundreds of years old.

"He is a formidable opponent." Byleth nods to that.