Haki

"Now that we've covered the Four Emperors, let's talk about the Shichibukai."

Rubick said, "The Shichibukai are Pirates recognized by the World Government. They can travel freely through Marine territory and the Affiliated Nations. They can also openly plunder nations that aren't affiliated, along with any Pirates they come across. All they have to do is hand over a small share of the spoils afterward."

Zoro still couldn't get Hawk-Eye out of his mind. "That Hawk-Eye guy is one of the Shichibukai, right?"

"That's right. He's among the strongest of them, too. He used to spar with Shanks. But he keeps to himself and has no crew or territory. Being a Shichibukai is just a personal preference for him."

"As for their strength, they're unmatched by anyone below an Admiral, and a few can even hold their own against one."

Rubick pointed at them. "You two, on the other hand, are only at Commodore level."

Zoro asked, "What about you, old man?"

Rubick smiled. "I told you before, didn't I? Once you became my companions, I'd tell you my secret. My Devil Fruit is extremely rare. It's the Copy-Copy Fruit, a Paramecia-type fruit that lets me copy other people's Devil Fruit powers."

"In other words, if I met one of those three Admirals, I'd have an Admiral's strength. If I met Fleet Admiral Sengoku the Buddha, I wouldn't lose to him. But without Devil Fruit powers, I'd probably be at Vice Admiral level."

Rubick held up two fingers. "You're still two levels below me."

Usopp said, "Only two levels? That's not so bad. Guess I'm doing pretty well."

Rubick brought him back down to earth. "I was talking to Zoro and Sanji. You and Nami have practically no fighting strength."

"That's brutal!"

Rubick said, "There isn't much I can actually teach you. But if you have some discipline and train your bodies every day, you'll keep getting stronger. What I'm about to tell you, though, is what truly powerful people need to master."

"What is it?"

Even Luffy stopped eating. Rubick said, "Haki!"

"You know Luffy ate the Gum-Gum Fruit. Punches and kicks normally do nothing to him, but Haki can hurt him."

Luffy cried out, "So that's why Grandpa's punches hurt so much! He was using Haki?"

Rubick went on. "Zoro, remember the Smoke-Smoke Fruit power I used before?"

"That one? Physical attacks couldn't touch you. You could just crush anyone."

"Exactly. That's how overwhelming Logia Devil Fruits are. Their users become natural elements, so ordinary physical attacks can't hurt them. But Haki can strike a Logia user's real body."

Rubick summed it up. "That kind of Haki is called Armament Haki. You can coat your body with it for defense or apply it to a weapon to make your attacks stronger."

Zoro asked the obvious question. "Then can you show us, old man?"

"Ahem. I can't use it."

"Tch."

"Boo!"

Rubick hurried to explain. "Haki is an ability you awaken by training yourself relentlessly. I'm not even in as good shape as Zoro. How would I have Haki?"

Something clicked for Zoro. "If I had Haki and coated my swords with it, I could cut through steel, right?"

"You could even cut through a meteorite! Dream big, then train hard. Once your body reaches a certain level, you'll be able to master it."

Sanji said, "There are other kinds of Haki, right?"

"That's right."

Rubick continued his lesson. "The second kind is Observation Haki. It's almost like mind reading. It lets you sense how an enemy will attack and respond ahead of time. Master it completely, and you can not only see the future but also hear the voice of all things."

Usopp asked, puzzled, "Then how do two people with Observation Haki fight? Do they just keep predicting each other?"

Rubick asked in return, "If I told you I was going to punch your chin with my right fist, could you dodge it?"

"Uh... well..."

Obviously, he couldn't. The gap in strength was too wide; knowing what was coming wouldn't help. Usopp stopped worrying about it.

But Rubick added, "For a sniper, Observation Haki is essential. It sharpens your senses enough to pinpoint an enemy several kilometers away."

Usopp raised his hand. "Coach, I want to learn that!"

"I can't use that either!"

Rubick said, "But I'm starting to get the hang of it!"

"What?"

The others perked up, but Usopp said flatly, "Blindfold yourselves with black cloth and spend a year or two living like you're blind. You might pick up the basics."

Zoro asked, "How do you know?"

"Because when the old man stayed in our village, he spent all day pretending to be blind and kept asking us to sneak up on him."

Rubick said, "There's no rush. Work on getting stronger first. Especially you, love-cook!"

Sanji snapped, "I'm a gentleman!"

Rubick ignored him and continued. "The last kind, Conqueror's Haki, is found in one person in ten thousand. It's incredibly useful for intimidating enemies. If their willpower is too weak, they'll pass out on the spot. That means you can't overwhelm someone with Conqueror's Haki just by throwing more people at them."

Rubick gave an example. "They say Shanks has the strongest Conqueror's Haki. If he unleashed it at Marine Headquarters, every Marine below Vice Admiral rank would be knocked out."

"What?"

"Is he even human?"

"So that's what a powerhouse is like?"

Usopp raised his hand. "Coach, I want to learn that!"

"I still can't use it. Someone as afraid of death as I am would never have Conqueror's Haki."

Zoro said, "Then could someone like me, who isn't afraid of death, learn it?"

Rubick was stumped for a moment. "Uh, I only know the basics of Conqueror's Haki. I've never even seen it myself. But I'm certain our captain has it."

Nami rolled her eyes. An idiot like Luffy really had an ability that powerful?

Rubick said, "Conqueror's Haki has to do with force of spirit, and you've all seen Luffy's. Who else could stand in front of everyone and shout, 'I'm the man who'll become Pirate King'?"

Nami shot back, "I thought you said he had no social anxiety. What does that have to do with force of spirit?"

Rubick retorted, "Then you try saying it."

Nami reached out and grabbed Rubick's ear. "Do you have to argue with everything I say?"

"I'm just telling the truth!"

Nami let go. Thinking it over, she realized Luffy wasn't simply free of social anxiety. He genuinely believed he could become Pirate King. She had never seen confidence like that before.