Kairo was a respectable young man; he would ignore the sound of fighting around him and focus on the old man's research, taking in every note he could find.
Twenty-four hours was way too short a time for a huge power boost, but if he forcefully pushed Zoro to almost die and brought him back over and over again, he could abuse the hell out of the Haki bloom mechanic.
If he wanted to abuse it more, he would need to use someone else, as using the same person over and over again diminished the effect of a Haki bloom.
He wasn't joking. There was a cap to how strong you could get fighting the same person repeatedly. If there weren't, Roger and Garp would be very OP.
The fact that they weren't suggested that cap did exist.
He began sealing everything the doctor owned. He pondered taking the bodies too, but he had no use for them, really. They weren't alive, plus it wasn't like they were super OP or had any cool Devil Fruits.
Meanwhile, with Zoro—
Zoro staggered three steps back. Blood ran down from his face to the floor. His breathing was rough. He was getting his shit rocked. He couldn't even see the man move; it was that fucking bad.
His Observation Haki was being pushed to its fucking limits, and his Armament Haki was doing jack shit against Ryuma, who seemed bored.
Speaking of the man, he stood across from Zoro, looking rather unimpressed by the guy's swordsmanship.
"Your guard collapses under pressure," the man said calmly.
"You overcommit to blows, leaving yourself exposed," he explained, before pointing at his sword.
"And that pathetic excuse you call Ryō is not worth it. It's horrible. I am surprised you made it so far with such weak skills." The man seemed colder than usual, his gaze dark as he stared at his own descendant. He wished the best for Zoro, but that didn't mean he would go easy on him.
He would make sure his descendant wasn't soft.
"I just learned Ryō a month ago," Zoro groaned. Shit, his body felt like hell. He immediately popped a pill.
His wounds began to heal at a speed visible to the naked eye. Yet at the same time, inside his body, his fat supply was being burned to fuel this; his cells were dividing like crazy.
Just like Luffy using Gear 2, every use of that pill took some time from his lifespan, but Zoro didn't care. He would pop a thousand pills if that meant he got the chance to grow stronger, to break past his limits.
"A month ago, you say?" Ryuma's gaze shifted to the Lunarian, who was currently in stealing and scheming mode, taking everything in sight while planting some kind of seals as if he were expecting visitors.
Something that looked like an Abyss seal.
Kairo was, in fact, placing an Abyss seal. He was destroying the highway that led to this island so the Holy Knights couldn't just spawn here.
That, however, would not stop other forms of teleportation, as a certain paw man was currently on his way to this island.
Ryuma turned to look at Zoro.
Well, time to continue putting belt to ass on his descendant.
Zoro kicked his third sword up from the ground with his foot, caught it in his hand, then slid it into his mouth.
He even had his durag on, so you know he meant business.
Three Sword Style.
Ryuma's eyebrow twitched slightly.
"Interesting."
They vanished again.
They clashed in the air.
Zoro pushed against him, deciding to forget all defense, pouring 100% of his Haki into offense and offense alone.
A diagonal slash ripped across Zoro's thigh. The impact alone spun him. Before he could recover—
A backhanded strike with the flat of Shusui slammed into his ribs.
CRACK.
Zoro hit the barrier hard enough to make it pulse.
Outside, Kairo didn't even glance up from wiping down a surgical table.
Inside, Zoro forced himself back to his feet.
Ryuma stepped forward.
No wasted movement.
He was called a Sword God for a reason. He blitzed toward Zoro.
Zoro barely twisted aside.
The tip pierced through his shoulder anyway.
Blood sprayed.
Ryuma rotated his wrist—
And carved a second line down Zoro's side.
Zoro's vision blurred for half a second.
He tried to block all of Ryuma's strikes, but like Bonnie Blue's womb, he got no break. Black sparks flew everywhere.
Ryuma's knee drove into Zoro's gut.
Air left his lungs in a violent wheeze.
He dropped to one knee.
Ryuma placed the blade against his neck.
"You are not ready."
Zoro's eye twitched.
He bit down harder on the sword in his mouth.
With a guttural roar, he forced his body forward—
And let his own neck slide against the blade just enough to close the distance.
Ryuma's eyes sharpened.
Zoro twisted mid-fall and slashed upward with both hands—
A desperate, ugly angle.
Ryuma moved to parry—
But Zoro altered the trajectory mid-swing.
The tip of Wado Ichimonji barely kissed Ryuma's shoulder.
A shallow cut.
A nick.
Silence.
A single bead of blood rolled down the Sword God's arm.
Ryuma looked at it.
Then at Zoro.
"...Good."
A/N...It will be mostly Zoro till 150, then after that its Luffy vs Moria.