After reaching home, Fujin thought, 'I guess that's the highest level of difficulty a rank B mission can get. Looks like my self-analysis of being Jounin level wasn't incorrect. Unfortunately, Konoha wouldn't promote me anytime soon. Also, tougher missions would mean that my life will be at more risk. My calculations were right. I should use this time to strengthen myself as much as I can.'

Fujin entered one of the rooms in the basement and turned on the lights. The room was empty. Fujin took out a scroll and summoned a few devices. There was a transformer, an Ammeter, an Ohmmeter, rubber boots, rubber gloves and a few wires.

Fujin wore the boots and began arranging the set-up while thinking, 'In order to avoid suspicion, I memorized the training process for all five elements long back. Only training methods for Yang and Yin elements aren't available in the library.

For the Lightning element, the way to train is a bit complicated as compared to Wind and Earth. Though at the same time, it is straightforward. I just have to endure shocks in increasing intensity to master it.

I will first need to measure the resistance of my body. And then I will have to use the Transformer to subject my body to increasing voltages. That will induce a current to flow through my body.

Even that has to be done in phases. My limbs can endure a higher current. But if a current passes through my heart or brain, then it could be lethal. Those two parts will have to be trained separately.

Anyways, the first step of learning Lightning release is being able to withstand 10 Ampere current through my whole body for one minute. The second step is to produce that much current on my hands. With these 2 steps alone, I will be able to learn Lightning jutsus up to rank B. Rank A and S will need me to be able to resist and produce a stronger current.

That said, increasing the intensity of the current that I can produce will strengthen the lower-ranked jutsus. Of course, on the flip side, I can use rank C and lower jutsus after being able to produce a current of 100 milliamperes. But it won't be very strong.

Fujin completed the setup. He created a Shadow clone to control the voltage. The setup had 2 open-ended wires. Fujin grabbed one with his left hand. He taped the 2nd wire to his upper arm. This way, the current would enter his hand, pass through his arm and leave through the wire attached to his upper arm.

The clone set the output of the transformer to 10V and switched it on. The current began flowing through Fujin's body. A number appeared on the Ammeter which was attached to the circuit. It read 0.125 mA.

Fujin began calculating, '0.125 milliamperes for 10 Volts would mean that my body resistance is 80,000 Ohm. The scroll said that I should be able to feel the current when it reaches 1 milliampere.'

He looked at his clone and said, "Increase it to 80 Volts."

His Clone nodded and increased the output of the transformer. Immediately, Fujin began to feel a slight tingling sensation through his arm.

Fujin let the current flow through his arm for a minute. He looked at his clone and said, "Increase to 200 volts."

His clone increased it. The current rose to 2.5 mA. It still wasn't painful for Fujin. Fujin recalled the details in the scroll, 'The Scroll was right at stating that we will feel the current at 1 milliampere. At 5 milliamperes will feel very disturbing to a normal human being, but it won't be very painful.

From 6 milliamperes, it will start getting painful. From then on, the muscles will start losing control. If a normal human is hit by this, he will just let go of the object that electrified them involuntarily.

This story originates from a different website. Ensure the author gets the support they deserve by reading it there.

Beyond 17 milliamperes, a normal human will begin experiencing extreme pain. He can't let go of the object and there is a chance of death.

Beyond 100 milliamperes, pumping of the heart becomes uncoordinated and nerve damage begins. At 2 Ampere, there will be a high chance of cardiac arrest, internal organ damage and severe burns. Death becomes very likely.

But, as a ninja who has trained my body using chakra, my endurance could be higher. It will still be very dangerous though. I should be very patient once it begins to hurt.'

He said, "Increase it to 400 Volts."

The clone increased it and said, "Don't forget that the body's resistance will suddenly decrease after 500 Volts."

Fujin nodded and said, "Yes. But the decrease in resistance is due to the outer layer of the skin breaking down. Due to my training, it might be higher for me. Anyways, keep an eye on the Ammeter. If the value suddenly begins increasing, turn the switch off. A second or two of high current won't be lethal. Besides, there is also the fuse which will melt at 100 milliamperes."

[A/N: Never thought I'd end up reading some research papers for writing fanfic! Anyways, the above data is true irl (though there can be some variations). The formula for calculating Resistance that Fujin used above is R = V I. A normal human body has resistance between 1k and 100k Ohms depending on some factors.

PS: This goes without saying, but don't try anything like this at home. Fujin is able to survive and adapt only due to chakra. So, don't try unless you can use chakra. If one of you has transmigrated from Naruto World to here and knows how to wield chakra, please let the rest of us know how to use it too. :-)]

The clone nodded. Fujin kept raising the voltage slowly. After half an hour, the clone had increased the output of the transformer to 4000 Volts! A 50 mA current passed through Fujin's arm.

Fujin thought, 'Finally I can feel some pain! Looks like my endurance is around 8 to 10 times higher than a normal human when it comes to electricity.'

He took some time to get used to the pain. Once the pain subsided, he increased the Voltage more. At 5000 V, the reading on the ammeter was 62.5 mA. However, it suddenly began increasing rapidly! The clone immediately turned the switch off.

Fujin let go of the wire and removed the one he attached. He shook his arm a few times and said, "That hurt!"

The clone chuckled and said, "62.5 milliampere in under an hour is great progress."

However, Fujin shook his head and said, "This is just the natural endurance I have developed over the years. The main training will start from now onwards. I have a feeling that this will take a long time just to reach the necessary endurance."

He thought, 'I wonder how Sasuke managed to learn lightning Release and master Chidori in under a month. Was it just his talent and the Sharingan? Or does Kakashi, no, the Hatake clan have a better way to master the Lightning Release?'

Fujin repeated the same training for his remaining 3 limbs. He followed it up by sending current from one hand to the other, allowing the current to flow through his chest. He started low and stopped at 5 mA. He repeated the same for a current to pass from the top of his head to the ground after removing his shoes.

Fujin trained this way for a week. By then, he could endure currents of 500 mA passing through his limbs and 100 mA through his whole body. He also managed to generate a current of 250 mA on his hand.

In these 7 days, in order to avoid any suspicion, he also went to the training ground for an early morning workout and after lunch to practice his Wind Release and Wind Vacuum Technique for a couple of hours daily.

The Lightning training also had a great effect on Fujin's physique. Fujin noticed, 'In addition to learning Lightning release, this method has a great effect on my body. I can feel my body getting slightly stronger due to those electric shocks. Though I guess that it will become ineffective after some time. Just like the Senju Taijutsu style increased my Chakra. Still, this physical buff will be very helpful.'

For the next couple of months, Fujin focused on training his Lightning element. The Lightning training along with the intense morning workout had done wonders for his body. He now operated the training seal at 95% capacity.

During this time, his team did 7 rank B missions. Having seen his capabilities, Fujin was given a much more active role in the team. Unfortunately, the missions weren't very challenging.

Finally, Fujin managed to generate 10 Ampere current. He and his clone grinned as they read 10A on the Ammeter.

Fujin said, "Time to learn Lightning Ninjutsu now. You go to the library. Check out the jutsus of Lightning, Fire and Water release."

The clone nodded and left. Fujin meditated in the meditation room until the clone sent the info back.

The clone began going through all Fire, Lightning and Water jutsus in Sections E, D, C and B. Of course, he only read the Lightning jutsus with full focus. As for the Fire and Water element scrolls, the clone analyzed the Lightning jutsus he read while pretending to read those scrolls.

After a couple of hours, the clone dispelled and sent the information back!