In the black market of Eternal Night Island, Sig used the special products he brought down from Sky Island, such as Recording Shell and Recording Shell, to exchange for some Beli, and then bought several "Magnetic Compass" in one go!
Back in Foosha Village, Sig had already discovered that the Rumble-Rumble Fruit's power could indeed allow him to move at "electric speed," which is close to the speed of light.
Electricity travels at the same speed in a superconductor as light travels at the same speed in a vacuum; in fact, they share similar properties.
However, Sig now understands why Kizaru doesn't usually move at the speed of light.
If reaction speed is insufficient, even light-speed movement within visible distance will encounter problems during body reconstruction, resulting in a slow reconstruction speed and revealing weaknesses.
As for long-distance movement beyond visual range, since it completely exceeds the perception range of one's own Observation Haki, there is a risk that the Devil Fruit user will not be able to reassemble completely.
Of course, even so, the increase in speed is quite significant—as long as it's within one's reaction speed, that is, within the limits of one's Observation Haki, the speed of short-distance movement can be maximized!
At this moment, when Sig transforms into lightning and "moves at high speed," his movement speed is only related to the reaction limit of his Observation Haki...
In other words, as long as Sig's Observation Haki reaction speed surpasses that of his opponent, he can be so fast that his opponent cannot detect him!
Sig doesn't believe that Kizaru, who has had the Glint-Glint Fruit for a long time, would be weak in Observation Haki —he probably focused on developing his own Observation Haki.
For the Glint-Glint Fruit and the Rumble-Rumble Fruit, Observation Haki extremely high "cost-effectiveness," directly determining their top speed.
For long-distance travel, one needs to "rely on" something—like when Kizaru traveled to the Sabaody Archipelago in the original work, he flew over on a cannonball instead of traveling at the speed of light.
It's like constantly holding the cannonball as it moves!
In contrast, Sig initially thought that the basis for "electricity" was easier to find, as all that was needed was a conductor!
In theory, if a cable were laid between the two islands, Sig could use the cable as a support to travel at near the speed of light.
Sig also realized that this was an opportunity to "overtake on a curve".
When supported, Sig can safely transform into electricity and move at near-light speed within a conductor.
Although to the average expert, both "high-speed movement" and "near-light speed movement" are extremely fast, in reality, the two are not comparable at all!
Against the former, one only needs a reaction speed faster than Sig to detect it, but against the latter... for an opponent to detect it, they would need to use their reaction speed to match the speed of light—pure perception, no matter how strong, could never reach that level.
However, using it in battle is quite cumbersome.
Sig's initial idea was to use a "long conductor" as a weapon, which, after being thrown, would allow him to quickly appear at the other end, during which time Sig would be moving at the speed of electricity.
Back in Foosha Village, Sig had already tried it: by attaching a chain to the back of a spearhead, swinging the spearhead out, and nailing it to a tree trunk, Sig's figure would immediately appear at the spearhead.
However, after trying it a few times, I realized that this method wasn't very smart.
First of all, this "chain" is not convenient, unless the opponent is straightforward enough to catch it with their bare hands. Otherwise, if the opponent knows Sig's ability, they can simply dodge far away when Sig throws the chain!
With such a long chain behind it, the throwing speed is not fast at all. It would be more practical for Sig to use his Observation Haki to perform "high-speed movement" normally.
Sig then tried "Option 2," replacing the chains with extremely thin wires—this made the throwing speed much faster and the distance much farther, but it was also easier to cut.
While in the Foosha Village, Sig was obsessed with finding a material that was both conductive, lightweight, and extremely strong.
It's not that there aren't any, and in fact, Sig could think of one: if he could find a spider-like Zoan Devil Fruit, these problems would be perfectly solved...
Developing the "spider" ability allows one to spit out conductive spider webs during combat, within which they can move at near the speed of light, and in all directions, not limited to one or two directions.
However, the third fruit can probably only be suppressed when it reaches Sequence 4.
It wasn't until after setting sail, while using his "Seafarer" abilities to guide the Red Force, that Sig suddenly realized—electricity can be not only electric current, but also an electromagnetic field!
Compared to electric current, which requires a conductor to propagate, aren't electromagnetic fields... or rather, radio waves, ubiquitous?
In other words, there's no need to worry about the conductor; as long as there's a device capable of receiving "radio signals," it can serve as a reliable receiver!
If one could move wirelessly, no longer bound by "wires," the leap forward for Sig would be terrifying.
Unfortunately, Sig is not Vegapunk, nor Gage... Although he had used various wireless communication devices before his transmigration, it did not mean that Sig could conjure a wireless receiver by hand. In fact, he had no clue about the technology and did not even understand the principles.
Furthermore, there's no readily available radio receiving equipment in the world of One Piece—perhaps Den Den Mushi could? But Sig doesn't have Den Den Mushi Fruit, nor can he make Den Den Mushi receive his radio signals, and he's not even sure if Den Den Mushi work on the principle of radio communication...
Besides Den Den Mushi, the only other thing Sig could think of was a "Magnetic Compass".
If a pointer can Record the magnetic field of an island, can it also receive Sig's "electromagnetic field"?
After buying a few pointers, Sig started testing them. He first crushed the outer casing with a pained expression, only holding the pointer part inside—these weren't cheap items on the Grand Line.
Furthermore, Sig is not an island, so how to make the Magnetic Compass consistently receive Sig's electromagnetic field still needs further research.
Now Sig is going to try this, starting with the most obvious one...
Sig began to continuously discharge electricity onto the pointer—perhaps by doing so, it would memorize it?
However, things didn't go smoothly; the pointer didn't cooperate.
Then Sig dripped blood on it—a very mystical method—but it still didn't work; blood doesn't carry a magnetic field.
After several failures, Sig composed himself, suspended the experiments, and began his daily training.
One cannot neglect basic training in order to develop a new ability; otherwise, what's the difference between them and someone who neglects their strength in order to develop Devil Fruit ability?
In addition to his daily Fish-Man Karate and understanding of the Sea Power, Sig has now added a new project called "Electric Hammer Training" - when it comes to a real duel between masters, Sig has more faith in a body that has been tempered through countless trials than Elementalization.
Using electric current to train the body significantly increases efficiency, and because you're already a "crazy person," you don't have to worry about your body overexerting itself...
Compared to Fish-Man Karate, "Lightning Hammering" truly propelled Sig's body towards becoming a top-tier powerhouse.
Otherwise, Fish-Man Karate alone is more like a training method for generating power.
While it does come with physical enhancements, it's almost impossible to hone one's body to the level of Kaido or Big Mom through Fish-Man Karate —that kind of physique cannot be achieved through normal training.
But the "Lightning Forging" made Sig see this possibility!
Beneath the mushroom-shaped umbrella, Sig sat cross-legged, his body crackling with electricity. Upon closer inspection, one could see streaks of electricity flashing across Sig body. Although Sig grimaced slightly, his scales became even more lustrous, and even finer scales sprouted from them...