Fujin analyzed, 'The first improvement is increasing the amount of bullets I can fire. The ideal will be if I can fire ten rounds of this attack in less than a second. That will make trying to outnumber me very expensive in terms of life. This attack alone could force an army to retreat. Of course, that is if that army isn't suicidal like the one that fought the Third Raikage until he died.
The second improvement is to increase my control over these bullets. Right now, I can change the direction, in which I want to fire the bullets, by pointing each finger in a different direction. But once I fire it, I can't control it any longer and it only travels in a straight line. Also, I can't twist my fingers too much.
But if I can make the bullets curve in the air, or better, get the ability to freely change their direction mid-flight, then it will add even more aspects to this jutsu. It will completely make all preparations against me completely redundant.
And the last and the most critical improvement needed is speed. Though the speed of these bullets is higher than my Vacuum Sphere, it is much slower as compared to the Vacuum Bullets I shoot from my mouth. In fact, it is even slower than the Air Bullet jutsu.
At this speed, the jutsu wouldn't be as effective as I wanted it to be. Though it will still add a new dimension to my fighting style, it won't be that threatening. After all, those Iwa ninjas could dodge the Vacuum Bullets consistently.
In addition to the above, I also need to decrease the amount of time I need to create and launch the jutsu. But that will keep decreasing just like it did during the last three days.'
Fujin analyzed for a bit and decided, 'I will start by working on the speed aspect. I'll move on to the other two improvements once its speed is at least greater than the Air Bullet jutsu.'
Fujin began working on the jutsu again. Since he was only working on the speed of the bullet, he created 3 Shadow clones and worked with just one bullet at a time.
Fujin and his clones worked on the jutsu for around half an hour. A frown formed on Fujin's face. He dispelled his clones and got their memories.
His frown deepened as he thought, 'I have made no improvements at all. Is this the max speed I can go?'
Fujin shook his head and thought, 'No. How can that be? There should be some method of increasing the speed. But, I will have to innovate because the normal method doesn't seem to be very effective.'
Fujin began thinking. However, even after 10 minutes, he couldn't come up with anything. Fujin sighed and muttered, "This is tough. I can't think of anything that could give me a breakthrough. When I shoot the Vacuum Bullets or Air Bullets from my mouth, I am able to give an additional push to it due to the wind chakra I gather in my mouth and throat and use it to blow the bullets.
But doing so with hands is difficult. For some reason, when I try to infuse wind chakra from my finger in the same way, the result is very subpar. I need a better way... Should I ask Hiruzen for help?"
Fujin thought for a few seconds before shaking his head. He thought, 'I'm sure Hiruzen would have some methods to resolve this. Even if he doesn't, he could apply the concept behind Tobirama's high-speed Water jutsus to Wind jutsus and teach me. But, I don't want to take such a shortcut. At least not yet when I haven't given it my all.
If I become dependent on him, then I will struggle a lot in the future when I try to develop even more advanced jutsus. Of course, if there is no choice, I won't shy away from asking him. I could think of at least a dozen ways of using the Will of Fire to make that old fox teach me.'
Having made his decision, Fujin immediately created Shadow Clones. A couple of dozen clones appeared next to him. All of the clones had very low chakra. They all sat down and began thinking about methods to increase the speed of the bullets.
Despite thinking for another hour, Fujin couldn't think of any good ideas. He looked at his clones and thought, 'I hope some of them had better luck.'
He dispelled his clones and received their memories. After organizing all his thoughts, Fujin analyzed, 'Hmm, nothing too revolutionary. The only decent idea I could come up with was using my own speed to grant more momentum to the Vacuum Bullets. But this isn't very promising. In combat, I might not always get the chance to move at a very high speed to provide momentum to the jutsu.
One way to overcome this could be by providing momentum by just moving my hand at a fast speed. However, it is a problem as well. My main reason for making this jutsu is to not give a lot of signs to show that I'm preparing Vacuum jutsu. The jutsu will lose its purpose if that is compromised.
Regardless, I don't have any better ideas. I will first try with increased momentum and then try to increase the amount of Wind chakra I infuse in the jutsu.'
Fujin extended his arm forward and began creating a Vacuum bullet in front of his index finger. Suddenly, he moved forward at a rapid speed while the Vacuum Bullet was still being created. As soon as the Vacuum Bullet was created, he shot it straight in front of him.
The Vacuum Bullet travelled at a high speed, piercing everything that stood in its way. Fujin analyzed, 'That's better. The speed is comparable to Air Bullet jutsu, though it is still slightly slower. Unfortunately, this method has one big weakness.'
Fujin began creating another Vacuum Bullet and moved at a high speed. As soon as the Bullet was prepared, he turned his hand towards his right and fired it.
The Vacuum Bullet began travelling towards his right. However, due to his momentum, the Vacuum Bullet also moved forward. Fujin missed his target by a huge distance. And, the speed of the bullet was much slower.
Fujin thought, 'As I calculated. The momentum is only useful while firing the Bullet in the same direction. But which fool will keep standing at the same place in a battle? The technique is almost completely useless while firing in other directions. Not to mention, it will put a huge retrain on my fighting style.'
Fujin raised his right arm and thought, 'I wonder if the momentum from a jab will be sufficient.'
Fujin pulled his arm back, preparing to jab the air in front of him. A Vacuum Bullet began forming once again. He jabbed forward as fast as he could. The hand stopped exactly when the Vacuum Bullet was formed. At the same moment, the Vacuum Bullet was fired.
It travelled at nearly the same speed as the Vacuum Bullet Fujin fired earlier. Fujin analyzed, 'Hmm, not bad. It's faster than I expected. This is more usable in battle. Though it still gives a little clue due to my arm movement, it's probably better than puffed cheeks.
Unfortunately, the speed is still slower than Air Bullets. There is no point in comparing it to the Vacuum Bullets I shoot from my mouth. How can I increase it further?"
Fujin analyzed for a minute and concluded, 'I guess I could move at a fast speed while jabbing forward. The two boosts shout stack up and increase the speed to at least beyond the air bullet. But it still has the same weakness. I should instead focus on making my jab faster.'
Fujin suddenly had an idea. He thought, 'The Assassin's Rush jutsu works by expelling a large amount of wind behind me at a high speed. What if I create a smaller, localized version of this jutsu?
I could expel the winds just behind my elbow and move my arm forward at a high speed using the Assassin's Rush. It will not only increase the speed of my bullet but will also reduce the amount of time I need to jab and hence reduce the warning time that my enemy has.'
Fujin thought for a bit to analyze whether the idea was feasible. After a few minutes, he nodded and thought, 'Yes, this should be the way to go. Not to mention, I could also use this method to improve my Taijutsu. I can use a similar force to increase the speed of my punches and kicks. Maybe even the speed of my sword slash. In fact, I can even do a…'
Fujin's mind suddenly went silent as another idea appeared in his mind. A weird expression appeared on his face. He felt an overwhelming urge to facepalm himself.