At first, Gusion felt the smoothness of Yamato's skin under her thin clothes, then noticed her stomach slowly swelling. Apparently, this time Yamato wasn't using Seimei Kikan as she drank, but just letting the red bean soup pile up in her stomach.
As Yamato gulped it down, her stomach swelled rapidly, soon looking like a ball.
Again, Gusion marveled at the elasticity of people in this world. Early in One Piece, he wasn't surprised when Luffy ballooned up—after all, Luffy was a rubber man.
But later, lots of people would get fat after eating, like Kid—their bellies were as elastic as rubber, able to hold huge amounts without bursting.
Of course, Gusion thought this was also due to personal constitution—only the strong could be that elastic. If your body wasn't tough enough, overeating would still make you burst.
As Kaido's daughter and an oni, Yamato was born with a strong body, and years of growth had made her even tougher. So even with her stomach like a ball, she didn't look uncomfortable.
In fact, she seemed satisfied, patting her round belly. "I'm a bit full."
Just then, there was a tearing sound as Yamato's clothes split at the side, unable to take the pressure and ripping wide open.
Yamato, who identified as male, didn't care at all about such details, just a bit annoyed. "Haven't eaten like this in a while—my clothes are ruined! I really liked this outfit."
With her shirt burst, Yamato's massive, perky breasts bounced free, her rosy nipples hardening in the cool air. Her ample cleavage heaved with each breath, drawing Gusion's wide-eyed gaze.
Gusion, sitting at her side, saw everything. He quickly grabbed the edge of her clothes to cover her up. "Demonstrate first. I'll fix it for you tonight."
Yamato nodded, then took a deep breath. Gusion, through his hand, could feel some kind of rhythm starting inside Yamato's body.
Then, as Yamato slowly exhaled, she shrank like a deflating balloon, her stomach flattening back down.
During this, Gusion kept his eyes closed, trying to sense it, but honestly, just touching wasn't enough to really get the feel of this power.
When Yamato was back to normal, she looked at Gusion. "How about it, did you learn?"
Gusion was silent for a while, then shook his head and withdrew his hand. "It's a bit abstract, but I think I faintly caught something. I'll try it myself."
He started eating, soon ballooning up his own belly.
Imitating Yamato, he took a deep breath and slowly exhaled.
And… nothing happened.
A bit awkward, but Gusion didn't give up—he kept trying.
After several failed attempts, Gusion fell into thought.
In the original, the people who could use Seimei Kikan never explained how to train for it—it was just a given skill, so Gusion thought it'd be easy.
But now he realized it was hard precisely because the original never showed the process; everyone just naturally used it.
Like Yamato, who had just figured it out on her own. What could he do—just try to figure it out too?
Gusion kept trying for a bit, but though his belly didn't shrink instantly, he did notice that copying Yamato's breathing and muscle use did speed up his digestion—he didn't feel as stuffed.
"Let's get back to work. There's always tomorrow. I'll try again at lunch."
Gusion stood up, knowing he couldn't eat more now, so he decided to train and give Yamato some coaching.
"Gusion-dono, didn't you say you'd tell me a story? Tell it now!"
Yamato caught up, her worries gone as quickly as they came as if she'd forgotten about breakfast.
Gusion smiled. "Then let me tell you a story about a monkey…"
…
Time flew by. After a morning of work, Gusion and Yamato each carried a giant pot, sitting on a big rock in the mine, ready to eat.
"Gusion-dono, hurry up! What happened after the Monkey King was trapped under Five Finger Mountain?"
Yamato asked eagerly, like a reader urging the author for the next chapter.
"Don't rush, finish your food first and I'll continue."
Gusion smiled. He'd casually started telling her Journey to the West, and now Yamato was hooked.
Understandably so—Yamato was the type to get high reading Oden's diary, having grown up isolated in Wano with little entertainment.
Plus, the early story of Journey to the West was full of adventure, freedom, and color, perfect for Yamato, whose heart longed for adventure and freedom.
"Alright… By the way, Gusion-dono, how's your Haki training? When we get out, we have to team up to beat Kaido."
Yamato remembered that, as payment for hearing stories, she was supposed to help Gusion get stronger.
"My Ryuo is pretty skilled now. Observation Haki is just so-so, but what I really want to master is your fast-eating technique."
Gusion said. His Observation Haki wasn't low-level, but he felt far from the future sight level.
With Ryuo, his attack power had jumped a level, and combined with the Origin Seed giving him passive buffs, he was a long-lasting powerhouse.
"Then try again, Gusion-dono! My clothes are already ruined anyway."
Yamato picked up her bucket, baring her side, making Gusion almost avert his eyes, but he put his hand on her stomach anyway.
If he couldn't learn it at once, he refused to believe he'd never get it.
After another round of Yamato's wild drinking, her belly swelled again.
…
Meanwhile, in the Udon Prison surveillance room, Queen's forehead veins bulged as he watched. "They're going to finish all the red bean soup!"
Nearby, Warden Babanuki, with his elephant trunk belly, wiped sweat from his brow. "Queen-sama, please don't be angry. I've arranged for new supplies. You'll be satisfied, I promise."
Everyone in Udon Prison knew that Queen, one of the All-Stars, loved red bean soup. Anyone who dared take his soup was in for a bad end.
So even if prisoners had a lot of coupons, they wouldn't exchange for red bean soup. They didn't want to make Queen mad.
At the same time, on Onigashima, Kaido was also fuming after seeing this on the monitor.
"That brat—what exactly is he doing with Yamato!?"
Kaido glared at the screen, already pissed off from seeing this in the morning, and now even more so.
"Oh, don't be so angry. Yamato said she's just teaching him how to digest food quickly."
Maria laughed, surprised to see this side of Kaido.
"Hmph."
Kaido snorted and said nothing more, but he was still annoyed.
Mainly, he'd spent the whole morning listening to Gusion tell silly myths and legends, never getting to the educating Yamato scenes he expected.
Plus, he suspected Gusion made up his stories—wasn't the Bull Demon King a bit too much like him? Kaido was not amused.
Still, seeing Gusion seemingly guiding Yamato toward normalcy, Kaido decided to let it slide.
…
Back in Udon Prison, Gusion withdrew his hand, looking thoughtful.
"Well? Did you get the trick?"
Yamato wiped her mouth with her wrist, asking.
"I think I get it. This strange absorption isn't just your stomach working."
Gusion mused, "It's like, in that instant, your whole body absorbs the food, with the stomach as the central hub."
Yamato grabbed a pancake. "Didn't really get that, but as long as you learned something."
Gusion's analysis wasn't wrong. After two sessions of observation and touch, he concluded Seimei Kikan was a whole-body absorption ability.
Normally, people digest food in the stomach and then send the nutrients throughout the body.
But with Seimei Kikan, it's way faster and more intense. In that instant, every cell in the body links up with the stomach and absorbs energy, as if every cell was digesting.
This made digestion super fast, and because the cells got the nutrients directly, rapid metabolism could heal injuries.
If, like Yamato, you weren't injured, every cell would act as a mini-warehouse, storing energy to be released when needed.
Once the energy exceeded storage, the body would transform to hold more, using the excess for that transformation.
The result: boosted physical stats.
Since the body naturally seeks balance, increasing physical stats also slightly boosts strength, agility, etc.
So Gusion felt he'd discovered the leveling scale in the One Piece world: eat!
Luffy's stats definitely increased throughout the story—not just from combat, but from the long-term benefit of Seimei Kikan.
After some thought, Gusion recalled the feeling from earlier, took a deep breath, and tried to get his whole body to absorb the food in his stomach.
Even after several deep breaths, he didn't succeed, but it wasn't a total failure—his stomach felt less full.
Gusion's eyes lit up. "Yamato, let me try again tonight. I think I'm close to figuring it out."
Yamato agreed without hesitation. "I hope you learn it soon. I'm counting on you to get stronger so we can beat Kaido together."
On Onigashima, Kaido's forehead veins bulged even more as he watched.
After eating his fill, Gusion looked at the old, weak prisoners who couldn't get enough to eat, then turned to Yamato, a new question forming in his mind.