The most prominent ability of Observation Haki is enhancing the perception of the five senses and even the sixth sense.
In the Skypiea arc, Gan Fall described Mind Net as "the power of listening." As long as the human body moves, it emits sounds. By mastering the power of Mind Net, one can hear these sounds and thus predict others' actions. With practice, the range can be expanded.
Enel also explicitly stated that he could combine his electric body with Mind Net to hear the conversations of all residents in God's Country.
Since it involves listening, the Rumble-Rumble Fruit can enhance this "listening" ability by spreading electric waves based on Mind Net, or rather, Observation Haki.
Chronos had already mastered Two-Colored Haki during his six years with Whitebeard. After eating the Rumble-Rumble Fruit, similar to how Sabo could immediately wield power after eating the Flame-Flame Fruit, Chronos could directly utilize its strength.
Using his naturalized thunder body, Chronos spread invisible electric waves and used Observation Haki to receive all the information transmitted back by these waves.
Filtering out useless information and quickly capturing the useful parts—this is what Chronos is currently practicing.
Skills like God's Judgement, 1 Million Volt Discharge, 20 Million Volt Discharge, and even 200 Million Volt Discharge, which Enel used in the original plot to directly unleash the power of the Rumble-Rumble Fruit, Chronos could also use after adapting to the fruit for a short while.
This method of application is almost like channeling all one's Haki into a single punch—something Chronos could master quite easily.
In contrast, skills like Enel's 30 Million Volt Thunderbird, Thunder Beast, 60 Million Volt Thunder Dragon, and even Thunder Metallurgy, which require shaping and precise control, require Chronos to practice before he can use them effectively.
Just like how the strongest display of Destruction God Beerus in Dragon Ball Super wasn't casually destroying planets, but rather, in response to Bulma's slap, he retaliated with a slap that merely knocked her to the ground.
Precisely controlling every bit of one's power is far more difficult than unleashing it all at once.
Chronos looked toward the Shandia direction, a flash of electric current at his fingertips as electric waves brought distant sounds to him.
"Blue Sea People! The gold of Shandora does not belong to you! It only belongs to the friends of Shandia!"
"Fufufufufu, you're right, but now... all I see is a flag~"
Hearing the clear words, Chronos frowned.
Is Doflamingo this arrogant now? Is it because he hasn't met Kaido, or does he mistake Shandora's gold for the World Government's Celestial Tribute?
"Some voices disappeared over there? Are they our friends?"
Angeles walked over, having sensed through Mind Net the disappearance of many voices in the Shandia direction. Seeing the visible coldness on Chronos' face, she asked.
"Yes, there's an overconfident flamingo who thinks he can snatch food from a tiger's mouth."
Chronos said with a darkened expression, crackling electric currents dancing wildly across his body.
These past few days, Angeles had proven her natural talent for Mind Net.
Just like Aisa, the Shandia girl from the Skypiea arc who was born with an awakened Mind Net, her perception range was almost equal to Enel's without any training, even capable of detecting Enel's position to provide intelligence.
Skypiea truly is a place of outstanding people and spiritual energy, producing geniuses in Observation Haki in droves.
"Pops, someone is bullying our friends. I'll go make them pay!"
Chronos reported, crackling arcs of electricity around him betraying his foul mood.
"Hmm?"
Whitebeard straightened up, looking toward the direction of Shandia in the distance, his face instantly darkening.
"Men, change course! Someone is destroying our friendship!"
Crack, crack, crack...
Just from his anger alone, the surrounding White White Sea began to fracture, a seaquake about to trigger a tsunami.
The originally lazy atmosphere suddenly shifted, the Whitebeard Pirates now radiating a murderous intent.
The newly joined Angeles stared wide-eyed, stunned by how quickly the mood had changed.
"Go, Chronos. Don't let our friends fly our flag in vain."
Bzzz...
As Whitebeard's words faded, Chronos' body dissolved into a flash of electricity, leaving only a glimpse of blue light and a faint sound drifting in the air.
...
Shandora.
Doflamingo twitched his fingers, more and more Shandians collapsing to the ground, specks of blood staining the earth, making the smile beneath his sunglasses grow wider.
Nola thrashed wildly, spraying venom and whipping its tail, but Doflamingo didn't even glance at it.
Sticky Launch Cannon!
Trebol puffed out his chest, his seemingly bloated body undulating like mucus, firing human-head-sized pellets directly at Nola.
The power of the Paramecia-type Sticky-Sticky Fruit activated.
Continuous slapping sounds echoed as Nola was struck by the pellets, its massive maw glued shut as if coated with adhesive, unable to open or close. Venom secreted frantically, slowly corroding the mucus, but more kept coming.
The enormous body made for an ideal target. The sticky bombs exploded, bonding Nola to the ground, making escape nearly impossible.
Nola writhed violently but was as powerless as a mouse trapped on glue paper.
Land Army Flag!
Another strange ripple spread out, the originally solid ground beneath Nola undulating like ocean waves.
Its body shaken by the shifting earth, Nola couldn't muster its strength, its tensed muscles going slack.
Diamante drew his sword, soft as silk, and with a flick, it regained its iron-hard substance.
Focusing his energy on Nola, Diamante swung fiercely, the blade releasing a powerful sword aura that cleanly split the earth in two.
Crescent Burial!
"Roar!"
Nola screamed in agony, a long gash bursting open on its body, the cut deep enough to reveal bone.
The massive serpent finally crashed to the ground, too severely injured to rise again.
"Whew~"
Diamante exhaled in relief, wiping the fine sweat from his forehead.
"Finally down, this beast!"
He cursed under his breath. Nola's vitality had far exceeded the expectations of these two top executives of the Donquixote Family.
Trebol's sticky bombs packed power comparable to rocket launchers, yet they couldn't even break through Nola's outer skin.
If not for Diamante recently consuming the Ripple-Ripple Fruit, allowing him to alter material forms and thereby comprehend the Cutting Steel Realm, he would have narrowly broken through to the Sword Master level.
These two wouldn't have been able to breach Nola's surface defenses at all.
It was only then that Doflamingo turned his head, his face showing approval.
For him, defeating Nola was simple. The cutting attacks from his slender strings were most effective against such colossal creatures, even through their tough exterior. Other areas were even easier—eyes, nostrils, mouth—Nola had far too many weaknesses.
Doflamingo undoubtedly possessed some talent. The String-String Fruit had been developed quite well in his hands, and in the original storyline, it even reached the awakened state.
After witnessing the Whitebeard Pirates vanish into the sky, Doflamingo soon realized they might have found Skypiea. Driven by greed and youthful arrogance, he used the power of the String-String Fruit to gradually hook onto clouds in the sky, hauling himself and his two subordinates up to Skypiea through sheer effort.
Intelligence had been gathered: the Knock-Up Stream existed around Jaya Island, and Doflamingo naturally assumed the Whitebeard Pirates had used this natural wonder.
What followed was obvious. Doflamingo and his men easily located the upper half of Jaya Island—the only landmass there.
When he saw the Golden Hometown, Doflamingo's heart skipped a beat. This was wealth comparable to that of an ordinary Celestial Dragon!
No—even ordinary Celestial Dragons didn't possess riches on the scale of this City of Gold!
Skypiea was sparsely populated. With only three of them and the power of the String-String Fruit, Doflamingo believed they could come and go as they pleased.
All they needed to do was eliminate everyone here, take all the gold they could carry, and even the Whitebeard Pirates wouldn't be able to track them down.
The only minor complication was figuring out a legitimate source for the gold afterward. But that was a trivial issue—the profits were more than enough!
After learning that the Whitebeard Pirates had just left, Doflamingo, consumed by greed, acted without hesitation.
Using the String-String Fruit to control the largest group—the Shandia—he sent Trebol and Diamante to deal with the massive unit, Nola.
Doflamingo's plan was total annihilation, so he didn't kill immediately. Instead, he focused on infiltrating all the Shandia with his strings.
Sending his subordinates to handle Nola was both a division of labor and a way to train them.
Doflamingo arrogantly believed everything was already under his control.
"Well then…"
He turned toward the Shandia Chief. The old man was already weeping, his body covered in blood.
Doflamingo's sunglasses hid his expression, but instead of softening his sinister aura, they made him appear even more evil.
"Foreve—"
Boom!
Thunder roared with terrifying force as Chronos made his heroic entrance, his icy gaze meeting Doflamingo's eyes beneath the sunglasses.
Zap!
A lightning pillar several meters wide crashed down with Chronos's arrival, engulfing Doflamingo entirely.
The electric current was so intense it could almost be described as plasma. Inside the pillar, Doflamingo's body was violently invaded and scorched.
One second, two seconds, three seconds…
Chronos showed no mercy.
Simultaneously, using Observation Haki to detect the strings Doflamingo had entangled around the Shandia, Chronos flicked his fingers, sending a spark of electricity flying.
The nearly imperceptible threads caught the current.
Sizzle!
Intense heat erupted, and the strings were instantly melted.
The instant the fine threads snapped, electricity scattered like heavenly blossoms, only to reconnect and melt the threads again, scattering once more, melting again, scattering again...
Under Chronos' control, a small cluster of electricity endlessly divided. Before Doflamingo's electrotherapy session could conclude, all his fine threads had already been severed.
Zzzzt... Zzzzt...
After nearly ten seconds, the lightning pillar finally dissipated, revealing Doflamingo who was charred black like charcoal, emitting wisps of heat like a overcooked steak.
Thump—Doflamingo collapsed temporarily unconscious.
"Doffy! What's happening?!"
"That... that lightning, that power—is that the Rumble-Rumble Fruit?!"
Even with his glasses on, Trebol could see everything clearly under the dazzling lightning, which made it all the more unbelievable to him.
The power of the Rumble-Rumble Fruit? How could this be? How could such a thing happen!
"Release the young master!"
Diamante, loyal to the core, snapped back to reality and raised his sword to charge at Chronos.
Chronos merely raised an eyebrow and lifted two fingers without a word, releasing two bolts of lightning.
Boom! Boom!
Amid the flashing lightning, both Diamante and Trebol were engulfed by the lightning pillars, subjected to the electricity's wild assault.
When the lightning pillars faded, Diamante's body had turned into blackened charcoal, his eyes vacant as he collapsed to the ground, unable to rise again.
As for Trebol...
"Hmm?"
Chronos frowned, noticing that after the lightning pillar dissipated, Trebol was merely panting heavily. The mucus covering his body had completely evaporated, revealing his disgustingly emaciated form.
"Did his protective coating help him avoid disaster?"
Chronos pondered thoughtfully.
"There are still flaws in the Rumble-Rumble Fruit's power. I'll need to develop it further to resolve this in the future."
Had the mucus on his body absorbed some of the lightning pillar's force, reducing its damage?
While unleashing overwhelming firepower was satisfying, the actual damage output wasn't high enough—precision strikes were still necessary!
Trebol stared at Chronos in disbelief. You call this a flaw in the Rumble-Rumble Fruit?!
Boom!
Chronos raised his hand and unleashed another lightning pillar. This time there were no issues—Trebol followed in Diamante's footsteps.
Next was...
With lightning flickering between his fingers, Chronos turned his gaze back to Doflamingo.
In the original storyline, Doflamingo was quite adept at deception. If Trebol could withstand one hit, there was no reason why Doflamingo—with his superior Devil Fruit mastery—couldn't, unless he was weaker than Zoro or Wyper during the same period.
Through his Observation Haki combined with electromagnetic sensing, Chronos clearly observed numerous threads protecting Doflamingo's vulnerable internal organs.
In an extremely short time, the fine threads had formed a structure similar to a Faraday cage, blocking the electrical current.
Though he appeared charred black, Doflamingo was actually in decent condition.
The electric current had merely paralyzed his nerves, preventing him from getting up for the time being.
This situation highlighted the common criticism of the Rumble-Rumble Fruit—it could basically one-shot opponents but couldn't deliver fatal blows.
Both the Skypiea arc scenario and the current situations with Trebol and Doflamingo before Chronos confirmed this point.
But it wasn't a major issue. Chronos had only recently consumed the Rumble-Rumble Fruit—he could develop it gradually over time.
From Chronos' observations, this limitation likely related to the unique physiology of people in the pirate world.
In this superhuman world, the physical laws of the real world naturally didn't apply.
The lightning attacks of the Rumble-Rumble Fruit are a combination of physical and magical damage—physical in aspects like scorching heat and paralysis, magical in being energy-based attacks.
Simply put, the Rumble-Rumble Fruit's attacks can deplete an entire health bar as magical damage, easily reducing it to a sliver of health. However, completely emptying it is somewhat difficult. It can inflict numerous negative status effects but rarely proves fatal.
The existence of Haki, or life energy, grants people in the pirate world robust vitality. This means they inherently possess considerable magic resistance and recovery ability.
Aside from fatal injuries like decapitation, heart removal, or disembowelment, as long as they aren't killed instantly when beaten to the brink of death, there's a chance for recovery.
Unless one is naturally frail or suffers a direct fatal wound, the semi-magical damage of the Rumble-Rumble Fruit—direct electric shocks—easily incapacitates but seldom kills.
Moreover, beings like Trebol and Doflamingo can use their own abilities to create special structures that bear the damage from electric currents, reducing the impact of energy attacks and thus enhancing their endurance.
This situation is quite manageable. Drawing inspiration from Kizaru's development of the similar Glint-Glint Fruit—techniques like Yasakani no Magatama and Ama no Murakumo, which form physical structures from semi-magical components to attack.
Zzzzt...
Chronos clenched his hand empty, forcibly gathering the frenzied electrical currents together. Through compression, they coalesced into a semi-solidified lightning sword.
He poised to strike, but Doflamingo's body, in a state of shock, abruptly jolted awake. Moving eerily like a marionette controlled by strings, it attempted to flee from Chronos.
From the storyline—Enel performing self-administered CPR while in shock, Doflamingo autonomously stitching his internal organs after being semi-shocked by Gamma Knife and Gum-Gum Jet Stamp, Luffy's rubber awakening into Nika on Onigashima while in shock—it's evident that consciousness drives Devil Fruit abilities beyond physical limitations.
At this moment, Doflamingo's body remained paralyzed and charred, yet the String-String Fruit's power continued to operate, forcibly propelling his movement.
Internally, Doflamingo was seething with rage. Why had he been a step too slow! If only he had acted directly from the start! Ended it quickly! Damn it!
This highlights Doflamingo's character flaw: overconfidence or arrogance, coupled with a condescending belief that he can control everything.
The title "Devil Fruit Philanthropist" isn't for nothing—giving away the Gold-Gold Fruit, then the Flame-Flame Fruit.
And that famous line—"But after using Fujitora, I'll have to kill him."
But Chronos, fully prepared, wasn't surprised by this.
Zap!
Chronos transformed into a flash of lightning, instantly closing in on Doflamingo, and swung the lightning sword without hesitation.
Zzzzt...
Like a hot knife through butter, the lightning sword cleanly sliced open Doflamingo's abdomen, revealing internal organs wrapped in threads.
The moment the lightning sword left Doflamingo's body, Chronos released the compressed currents, causing the sword to explode violently.
Boom!
Frenzied electricity ran rampant, licking across Doflamingo's form.
Blood evaporated instantly upon contact with the lightning. With his organs exposed and flesh beneath the skin facing the thunder, Doflamingo collapsed onto his back, utterly incapable of rising again—breath faint, on the verge of death.
Chronos flexed his fingers indifferently.
Such is the power of the Rumble-Rumble Fruit. Defeating a Doflamingo not yet twenty years old is no more difficult than Enel besting Sanji and Zoro.
In less than a minute, the situation on the battlefield underwent a shocking reversal.
Chronos turned to face the Shandia with an apologetic expression.
"I'm sorry we're late, causing the Shandia to suffer such misfortune."
Doflamingo's mind was indeed sharp—merely by observing the Whitebeard Pirates' movements, he had directly uncovered the truth.
"No, you've arrived at just the right time!"
The Shandia Chief exclaimed with relief, as if granted a new lease on life.
At that moment, the Whitebeard Pirates made landfall, sharpening their blades and preparing to confront the invaders.
"Chronos, we're here! Where are the invaders?"