The ship sailed across the vast sea.
Riding the wind and cleaving the waves, the freedom pirates yearned for was something no one could resist.
"Satan, starting today, learn Armament Haki with me."
On the deck of the Moby Dick, Marco sought out Satan.
Satan was strong, but he didn't understand Haki. In the New World, you couldn't survive without it. Even if Seize was powerful, against someone who could instantly coat any part of their body with Haki, he would be helpless.
"Alright."
Satan grinned.
That night, after speaking with Whitebeard and hearing what lay in his heart, he'd understood: to live freely on this sea, he had to become stronger. Beating the Great Whirlpool Spider had only been a start; he was still a ways from being a true great pirate.
Haki would be a fast way to raise his strength. Besides, Body Hunter Guard required him to take an opponent's blow to steal their power. Armament Haki would raise his defense and pair perfectly with Body Hunter Guard.
"Haki is a latent power all humans possess—spirit, killing intent, the will to fight. When you control what the eye can't see but the mind can feel, your will becomes a weapon. That great power is called Haki.
"There are three types: Observation, Armament, and Conqueror's.
"Among them, Conqueror's and the highest level of Observation are innate. They can't be gained through training. The highest level of Observation is even rarer than Conqueror's.
"Ordinary Haki can be improved through training.
"Today, I'll teach you Observation Haki."
Marco explained it in detail.
Observation Haki allowed one to sense fluctuations around them, to read attacks and danger. At higher levels, it could even glimpse the future.
"Next, I'll demonstrate Observation Haki. Attack me however you like."
Marco closed his eyes.
"Got it."
Satan didn't hold back. His fists surged, his legs whipped—each strike carried tremendous force.
Yet no matter how he attacked, Marco evaded with ease.
"Seize."
Satan reached to grab him—but Marco's body turned to flame. His hand closed on nothing but air.
"Observation Haki lets me sense danger," Marco said. "Your Seize is ghostlike, but I can feel it ahead of time and slip away."
"So that's the true reason you're called the Undying Bird," Satan realized. "A powerful Mythical Zoan paired with high-level Observation to avoid fatal damage, then recovery to return from the brink—together, it makes you 'unkillable.'"
The fruit was only part of it. The real reason lay in Marco himself. Even with great recovery, if the vital points were struck again and again, he would still die. With Observation Haki, it was different. The blue phoenix flames could, at times, behave like a Logia—tangible and intangible. In battle, Observation let him avoid lethal blows.
Then those with Logia powers who didn't fear Armament must also be using Observation to pre-empt the hits, right?
A faint smile tugged at Satan's mouth.
To counter Observation Haki, he would need Observation Haki. He had to learn it.
"Seize—Hunter's Festival."
Satan barked the words and swept both hands outward. Within ten meters all around, everything was seized at once.
Marco's instincts screamed—danger was everywhere at once.
"A ranged technique? What a broken ability," he muttered, growing wary.
Satan stamped forward, rushing him. Marco reflexively dodged—
—but caught the strange curl of Satan's smile.
Bang.
Marco was sent flying.
"I got you," Satan said with a grin.
"Impossible… Did you use Observation just now?" Marco stared in shock. He had only demonstrated the basics and hadn't actually taught the technique yet—had Satan already learned it?
Had this guy made him misread with Observation itself?
This wasn't how a beginner used it. How long did it take to learn Observation Haki? A month? Half a year? How long to wield it like an arm at your command? Two years? Five?
And Satan had just done it.
Was the kid truly a monster?
"Looks like I'm ready to learn Armament Haki," Satan smiled.
Hunter's Festival could strip the strength of every living thing within several meters and add it to himself. Without Armament Haki to block it, even Observation Haki couldn't escape his all-angle Seize—unless Marco slipped out of range in an instant.
For now, Satan's power only supported a range of a few meters. If he trained it to the extreme, miles around could become his to take.
Aside from Armament Haki, Satan had yet to find a nemesis for Seize.