Zoro's body lay limply on the floor. He had no energy left in the tank; his body was running on pure fumes and nothing more.
He was still alive, though barely.
Across from him, Ryuma could be seen, his sword oozing Conqueror's Haki. He was ready for a fight. While he wasn't as strong as the current strongest swordsman, his swordsmanship was still elite. He could probably rank third or fourth in this generation of swordsmen.
Behind Mihawk and Shanks, of course.
Kairo entered the barrier, his hands currently gently holding onto a scalpel that he was going to use.
While yes, Zoro was alive, he could tell it was barely. If he didn't receive any medical attention, he would die—and not just a small death, but a very big one.
He got to Zoro's body and crouched to his level.
He saw the deep gash on his chest and how the Conqueror's Haki seemed to linger in there, making sure his body took maximum damage.
As a doctor, he did his job. He sent a pulse of Haki through Zoro's body, using Observation Haki to see how it interacted with his body, to see how deep the damage went.
Zoro had fifteen damaged ribs—seven on his left side and eight on the right side.
He had severe muscle tearing in both of his arms. Some of his broken ribs were poking against his lungs.
He also had major lacerations across his abdomen with partial organ displacement.
His skull also had some cracks on it.
Kairo clicked his tongue.
"You are really tough." If he didn't know any better, he might have thought Zoro was anything but human. His durability was simply insane.
He decided to roll Zoro onto his back, and the man didn't react, the rising and falling of his chest the only sign that he was still alive—barely clinging on to life, but alive nonetheless.
Taking a deep breath, he sent Ryō into Zoro's back, using it in such a way that it fixed Zoro's spine.
Who said Ryō could only be used to do damage?
Anyway, he turned Zoro back around, taking out his scalpel. He had nothing to make sure Zoro didn't get infected. Hogback worked with the dead; his ass didn't keep much detergent for some unknown fucking reason.
Either he didn't carry them, or he simply didn't have any right now. Oh well, it didn't matter.
Using his Lunarian flames, he heated the scalpel. This way he would simply cauterize the wound.
"Let's stitch you up."
As those words left his lips, he began his work, David's soul fully in control. This had been his work back there; his hands were steady.
He carefully placed Zoro's intestines back where they belonged. You know, couldn't have that shit all messed up.
He ignored the blood in his hands. In medicine, he had heard that pain was better than no reaction. If your patient was in pain and screaming, that was good—it meant they were alive. You should only start to actually worry when they showed no reaction at all.
Pain was a sign that you were, in fact, still alive and could still feel.
He cleaned debris from the wound using a sterilized cloth he'd prepared earlier.
He began stitching Zoro's abdominal wall closed.
"This could leave a mark."
He could make sure it didn't. He had some collagen lying around; he could do it. And while plastic surgery wasn't his field, he was a surgeon. And while yes, there were different types of surgeons—like brain surgeons, heart surgeons, and all that stuff—he was deadass just a surgeon.
His heated scalpel occasionally touched the wound edges, cauterizing ruptured vessels before they could bleed out again.
Zoro's chest rose quickly and fell again. His wounds were being healed. Kairo decided to feed him one pill. As Zoro's unconscious body swallowed it, he watched as his wounds began to close, his body burning all extra fat in order to heal him.
Granted, Zoro would be hungry like a motherfucker when he woke up, but he was fine now.
Since Kairo had semi-fixed the ribs, the healing fully repaired them.
He had realized it by now—Zoro was stupidly tanky.
"He will be up soon," Kairo said, watching as Wado Ichimonji flickered to black over and over again, and Zoro wasn't using any Haki. It seemed like Zoro was finishing one of the requirements to forge a black blade.
"Why are you so sure? He is practically dead," the swordsman said, looking at Zoro's passed-out body on the floor.
"Well, for one, I know he will not die so easily," Kairo said, watching as Zoro's grip on his blade vanished, a thin layer of Abyss appearing around his body as his blade kept turning black and then returning back to normal over and over again.
Kairo knew how to forge a black blade. While he himself didn't have one, his ancestor had written down how.
{Theory: Not canon}
You see, he kind of viewed it like a Zanpakutō from Bleach. When you first get your Asauchi, you must imprint your will or soul upon it to make it into a Zanpakutō.
Now this step, but in One Piece—by pouring a shit ton of Haki into it, eventually the sword develops some kind of will of its own. That's the reason why black blade users usually refer to their blade as if it had sentience.
Though if that was all that was needed, everyone would have a black blade.
After that, your goal must be achieved with it. For Zoro, probably becoming the world's strongest swordsman.
If Momonosuke was given Oden's sword and was able to open Wano's borders and free it—shit, that would be a black blade made right there.
Kairo's brow furrowed a bit; all of the shadow in the room seemed to be vanishing. {Chapter 154}
A/N I think this fits.