Perfecting Ultra Instinct

"What a powerful ki... is this really Trunks?" After sensing this ki, Shin and the others were incomparably shocked. Just a few days ago on the unknown planet, Trunks' strength was still very weak. Of course, this was weak compared to monsters like Goten and Hit. But compared to themselves, Trunks was already ridiculously strong.

Now, the ki of Trunks had obviously improved qualitatively. This made them sigh; Saiyans were really a perverted race. Especially this generation of Saiyans—they were all monsters! Why had he never heard of such insanely powerful Saiyans before?

Just as they were in shock, the golden light around Trunks' body began to dissipate little by little. His appearance was presented in front of everyone, and his transformation was tremendous.

His whole body was covered with red hair, and he looked stronger. His hair color remained the same purple as before, which was completely different from Goku and Vegeta's hair color after becoming Super Saiyans. The pants damaged by turning into a Great Ape were intact again. This made Goten feel quite strange. It was probably one of the unsolved mysteries of the Dragon Ball world. After every transformation, the clothes were damaged, but the pants were never destroyed, just like the Hulk's underpants.

"This... this is the form of Super Saiyan IV? I can feel the strength in my body. I've once again made a qualitative improvement, which is completely different from before. It's really too strong." Trunks clenched his fists, feeling the power surging in his body.

He couldn't be more excited. He had never felt such powerful force. He didn't even think that one day he could become so strong!

"Is this the transformation of Super Saiyan IV? Such a big change has happened. It's amazing!" Shin and Kibito were also shocked. As for the Old Kai, although there were some changes in his complexion, the fluctuations were not great.

"That's nice, Trunks. I didn't expect you to successfully transform into the form of Super Saiyan IV so quickly! Now you can truly be said to have stepped into the ranks of top powerhouses in the multiverse," Goten complimented Trunks with a smile.

Being able to become Super Saiyan IV so quickly was obviously related to Trunks' royal blood. It would be great if he could become Super Saiyan IV so quickly. But now, Goten was still a little worried. For one thing, he didn't have the royal blood like Trunks. Secondly, he had already fused the blood of a Legendary Saiyan, which was of a more violent variant. After transforming into a Great Ape, he didn't know if he could control his sense of reasoning.

Trunks recovered from the excitement, looked at Goten, and said gratefully, "Thank you so much, Goten. Without your help, I would never have reached this level in my life and it would have been impossible to even know the form of Super Saiyan IV!"

Goten continued with a smile, "You don't have to belittle yourself, Trunks. Your talent is still very strong. Even without my guidance and help, you could definitely reach this level with your own strength!"

"Goten, after turning into Super Saiyan IV, I feel the power in my body is ridiculously strong. I don't know how far I am from you now. Can I ask you for a spar?" Feeling the powerful strength of his body, Trunks was also ready to take this opportunity to test Goten's strength.

Although he knew that even if he became Super Saiyan IV, he would never be Goten's opponent! He never thought of surpassing Goten with this form. He just wanted to feel Goten's power and see the gap between them.

"Sure, but you'd better be mentally prepared. Although your strength has become much stronger after becoming Super Saiyan IV, the gap is still very big compared to me," Goten nodded but reminded Trunks in advance. Even if he didn't transform into Super Saiyan, he was far stronger than Trunks.

"Ok, I know. I'm just purely curious," Trunks nodded. Then, his face became serious in an instant. While clenching his fists tightly, golden radiance spewed out from his body. The powerful force also spread instantly. The air waves under his feet spread round and round!!

"So strong... these guys are all too outrageous!" Feeling the strength of Trunks, Shin and the others were shocked again. Just a few months ago, they thought they were the strongest gods in the universe. It was absolutely impossible for mortals to surpass them! But in such a short time, powerful mortals appeared one after another. It seemed as if they, Kaiōshin, had long lost their former hegemony, not they weren't even qualified to being a foil to these guys.

After bursting out with all his ki, Trunks looked at Goten and asked, "Goten, don't you need to transform?" The reason he asked was because the power of Super Saiyan IV was really strong. At least in his opinion, it was very powerful.

"No, just attack with all your strength," Goten shook his head and replied. After he acquired Broly's bloodline, his basic strength continued to grow every day. After each battle, his strength would be greatly improved. Especially after training with Whis for more than a month, his basic strength had reached a rather terrifying level.

It was no exaggeration to say that even Super Saiyan Blue Goku and Vegeta from Dragon Ball Super could not beat his normal form. As for the Super Saiyan IV Trunks, his strength should be similar to that of Super Saiyan Blue Goku. Even if it was strong, it couldn't be too strong. So there was no need to transform at all!

"Good!" Trunks nodded seriously. He believed in Goten's strength! Since Goten was so confident, he must have the capital of self-confidence. Then, Trunks' body jumped out directly. In an instant, he was in front of Goten. There was a golden light around his body, and he punched out with all his strength! Faced with the full attack of Trunks, Goten's face did not change in any way. He just stretched out his right palm and calmly blocked.

Snap!! Rumble!

The moment their fists met, the ground under Goten's feet collapsed instantly. Ripple-like circles spread to the surroundings, continuously collapsing. But even so, Goten's body remained motionless. Obviously, even in the state of Super Saiyan IV, Trunks couldn't match the normal Goten.

"What a terrifying power!! Is this Goten's strength? He's just using his normal strength, and I hit with all my strength. The gap between us is still unimaginably large. Goten is really terrifying!" Shocked, Trunks immediately withdrew his fist.

There was no need to spar further! Even if he tried his best next, it would be absolutely impossible for him to defeat Goten. This unfathomable gap made him lack the courage to continue sparring. If the gap was too big, then the fight was pointless!

After retracting his fist, Trunks let out a long breath. Then he returned to his normal form. Now he had successfully transformed into Super Saiyan IV and had fully mastered this power. He felt like he could be in Super Saiyan IV anytime, anywhere. This form was different from the previous Super Saiyan II as it didn't seem to consume too much physical energy.

[T/N: CN author took the concept on how Goku in GT can't maintain SSj3 due to endurance requirements, but can maintain SSj4 as it boosts the body to peak state or smth.]

After seeing the battle, Shin and Old Kai hurried to Goten. Shin asked, "Goten, I see your tail has grown! Do you want to be like Trunks and transform into Super Saiyan IV now?" He was very curious. Goten's strength was so powerful, he didn't know how much his strength would improve after achieving this transformation. If nothing else, it should be far above Hakaishin.

"I don't think it's necessary for the time being. I'm not sure I can control this form. If I get out of control, I may destroy the entire God Realm, and even the Universe would be in danger of destruction."

"Besides, I haven't encountered too strong an opponent so far, so I don't plan to transform into Super Saiyan IV for the time being," Goten shook his head and said to Shin.

He was still very cautious. His basic strength was really too strong. Once he became a Great Ape and got out of control, the entire God Realm would definitely be destroyed! And these few people in front of him couldn't control him.

Furthermore, so far, no enemies too powerful had been encountered. So there was no need to change into Super Saiyan IV form. Now all that was left was to see Jiren's strength in the Tournament of Power! If that guy really had the power to surpass Hakaishin, then he would definitely have to become a Super Saiyan IV...

"Remember what you said just now! Don't go back on your words later!" After hearing that the God Realm might be destroyed, Shin immediately agreed. This was too dangerous!

"Okay, our purpose of coming to the God Realm has also been achieved. There are other things to do now, so I won't bother Kaiōshin-sama," Goten spoke to Old Kai and the others. Then he directly took Trunks back to Earth through Teleportation.

...

Back at Capsule Corp, Android 21 and Bulma were teaming up to create the pure android Krillin. Even if the two of them joined forces, it would take at least a few days! Goten and Trunks didn't bother them.

Krillin walked out of the research room immediately after feeling the aura of the two of them. The moment he got to Trunks, Krillin felt the difference in Trunks.

"Trunks, you have become much stronger! I didn't expect you to become so much stronger after only three days," Krillin looked at Trunks in surprise and said. He could feel a qualitative change in Trunks. This showed that Trunks had definitely made a new breakthrough in these three days!

"Yes, Krillin. It's all Goten's help actually. Without Goten's help, it would have been impossible to achieve the form of Super Saiyan IV," Trunks scratched his head in embarrassment and replied.

"Super Saiyan IV? It sounds amazing! Seeing that you have become so strong, I can't wait to become the Ultimate Android," Krillin looked at the two of them and said with a smile. He couldn't let the two of them drop him too far!

"Krillin, Trunks and I are going to the Hyperbolic Time Chamber for two years. Although Trunks has mastered the form of Super Saiyan IV and has also developed his potential, it will take two years of hard training in the Hyperbolic Time Chamber to better control this power," Goten said to Krillin.

For a Saiyan, the basic combat power was always the most important. If they trained in the Hyperbolic Time Chamber for two years, then after coming out, he promises that his strength would definitely surpass all Hakaishin! If he became Super Saiyan IV at that time, maybe even the Angels would not have the power to fight.

"Well, you guys go! I'll tell Bulma and Chichi later," Krillin nodded. Then the two went directly to the Lookout.

According to the previous regulations of the Hyperbolic Time Chamber, everyone could only enter for two days. Once it exceeded two days, they would be trapped in the different space of the Hyperbolic Time Chamber forever. But when the strength reached a certain level, one could break even the dimensional wall in the Time Chamber and come out from it.

And now, Goten and Trunks both had the power to break the dimensional wall of the Hyperbolic Time Chamber. So the Hyperbolic Time Chamber had no restrictions on them and they could train for however long they wanted in there.

...

As time went by, Goten and Trunks in the Hyperbolic Time Chamber were also practicing desperate training. A day passed in the blink of an eye outside, but in the Hyperbolic Time Chamber, a full year had passed.

In this year, the basic combat effectiveness of Trunks had also been greatly improved. Especially with Goten's guidance and sparring, his speed had improved even faster. The form of Trunks' Super Saiyan IV was also more stable. Originally, his Super Saiyan IV was not mastered by him. At this moment, he was trained by Goten to the point of perfection. In the past year in the Hyperbolic Time Chamber, apart from eating and sleeping, the two had been training desperately almost every moment.

At the moment, Trunks was training desperately alone. But Goten stood there, seemingly meditating. He had been in this state for three months.

He didn't train basic combat power every day but seemed to be comprehending something. He didn't need to train deliberately, because after obtaining Broly's blood, his basic combat power would basically increase rapidly every day. And now, he was just thinking about the perfect Ultra Instinct.

Whis' one-month training before also gave him a better understanding of Ultra Instinct. All this time, he had been concentrating on comprehension for three months. He also seemed to have finally grasped the true meaning of the perfect Ultra Instinct.

Right now, Goten suddenly closed his eyes. The whole person and momentum were in a very calm state. Trunks, who was training on the sidelines, felt that Goten was so calm, so he stopped training and looked over curiously. He saw silver lines and aura suddenly appear around Goten's body. This aura was getting more and more turbulent.

The next second, Goten suddenly opened his eyes. A silver crescent-shaped light flashed through his pupils. Immediately afterward, his black hair began to move automatically without wind. The silver aura around his body was also getting brighter and brighter, changing little by little. At the beginning, with the surge of spiritual energy, the surrounding temperature suddenly increased a lot. But at this moment, the temperature began to drop bit by bit.

Brush!

In the next second, Goten's black hair directly turned silvery white. The silver aura around his body was also more radiant, and the aura of the whole person became calm.

"So... is that the perfect Ultra Instinct?" Seeing this, Trunks murmured in surprise.