This is the main protagonist of the series, Goku, in his ultimate form. This form is the last of Goku’s tranformation seen in the Dragon Ball universe.
In this form, Goku looks completely different from any Super Saiyan forms that have appeared so far. He looks so menacing and fierce that it was hard for Pan to tell if he was good or bad. Goku in his Super Saiyan 4 features black and long hair. Super Saiyan 4 Goku’s upper-body is covered with red fur, and so is his tail, and his eyes are colored red when shut.
With the help of the Elder Kai, Goku was able to regrow his tail that was cut off from childhood to bring back the special abilities he had lost. With the tail back, Goku was able to maintain his Super Saiyan 3 form longer during his next meeting with Baby. However, Goku still proved no match for Baby and was easily defeated. After staring at the moon for a brief while, Goku’s tail triggered a metamorphosis that mutated him into a giant golden ape.
Goku went on a rampage and began to destroying things. Although the massive power that Goku gained from transforming into an Oozaru had made him more powerful than Baby, his size made it difficult for him to catch the small and speedy parasite.
Later, after seeing the tears of his granddaughter Pan, Goku finally regained his rationality to trigger yet another transformation into his ultimate Super Saiyan form, the Super Saiyan 4.
Goku’s Power Level
Fans tend to think that adding up the power levels of two individuals is the key to predicting the new power of the resulting one. Unfortunately, that is not the case.
Let’s take the Super Saiyan 2 as an example. When a Saiyan transforms into a Super Saiyan 2, it does not necessarily mean that he is twice as strong as a regular Super Saiyan. In fact, a Super Saiyan 2’s power level is 7 times greater than a standard Super Saiyan’s.
During the Android Saga, Cell absorbed Android 17 and 18 and attained his perfect form. During that time, Android 17 and 18 were programed to be each stronger than a Super Saiyan, which should have made Cell about as strong as a Super Saiyan 3 like fans would think, and it was clear that Cell was even far below Super Saiyan 2 Gohan.
When Super Vegeta battled Semi Perfect Cell, Vegeta’s power was 3 times greater than a Super Saiyan’s but still much weaker than a Super Saiyan 2. Also, the power level of any transformation in the series changes as time goes on, which means we cannot compare Super Saiyan Goku from Frieza Saga to Super Saiyan Goku in Cell Saga, as it is obvious that Super Saiyan Goku in the Cell Games is much stronger than the one that fought Frieza.
It is undenial that it only takes about a year for the likes of Goku and Vegeta to triple their strength, which was seen during the Android Saga, as Vegeta, Goku, and Future Trunks entered the Hyperbolic Time Chamber as mere weaklings who didn’t stand a chance against any of the androids, but upon emerging were packed with powers that rivaled even Perfect Cell’s. But what would happen if these Saiyans trained for more than a decade?
Keep in mind that right before Dragon Ball Z ended, Goku alone was the strongest non-fused being in the series as he had fully mastered his Super Saiyan 3, which would’ve been dubbed the Full Power Super Saiyan 3. This is the form that Goku lacked during the battle with Kid Buu and the very one that Vegeta spoke of.
The Full Power Super Saiyan 3 would be at least 5 times more powerful than its regular version and could rival Vegito and Gogeta in strength. If Goku had access to Full Power Super Saiyan 3, then Kid Buu would be nothing more than just a simple matter.
When Goku fought Uub in the World Tournament, Uub’s power fluctuated from very weak to as high as Kid Buu’s when he was provoked. Goku was fighting evenly with Uub at his base form, meaning that his power in his current form was already at least as strong as his Super Saiyan 3 during the fight with Kid Buu. GT was another 10 years after Goku’s fight with Uub, where he is even more powerful than before.
In GT, Goku’s power must have dropped by a considerable amount when he was turned into a child, which made his student, Uub, above him during the first half of the series, but even so, he is still way superior to any Dragon Ball Z warrior in terms of power. Though not obvious, due to constantly training his body before Uub was even born, in GT, Kid Goku in his base form is already much stronger than the Super Saiyan 3 that he used against Kid Buu, roughly equal to the previous Super Buu (with Piccolo, Goten, Trunks, and Gohan absorbed) in strength.
At Super Saiyan, Goku’s power multiplies by a hundred fold(the power multiplier used to be 50 during Dragon Ball Z, but now 100 as it changes over time), meaning that the magnitude of his power is roughly 100 times that of Super Buu’s. Even Rilldo was shocked when he saw the results of his computer after it calculated Goku’s monstrous battle power, stating that he’d never seen anyone with such a little body to have a power with a mind-boggling magnitude.
At Super Saiyan 2(though Super Saiyan 2 was never assumed by Goku as he knew it wouldn’t be enough to even budge Baby Vegeta), Goku’s power multiplies even more, and his power may be comparable to the old Super Vegito’s, and if things aren’t bad enough for his foes, Goku has one more transformation at his disposal: Super Saiyan 3.
While still a child in size, his Super Saiyan 3 now is several hundred times stronger than the ones he utilized during the Majin Buu Saga, meaning that Goku is now completely invulnerable to the most powerful villains from Dragon Ball Z who were only bounded by fusions.
The Super Saiyan 4, is the ultimate Super Saiyan form in the entire Dragon Ball series that possesses the overwhelming power of the Golden Oozaru with a newly acquired speed never been seen before. The massive power augmentation brought by this insanely powerful form is so great that it made Goku practically invulnerable to even Super Baby Vegeta’s most powerful attack, the Revenge Death Ball, and not long ago Super Baby Vegeta was tossing Super Saiyan 3 Goku around without much effort. The transformation is so powerful that it can temporarily undo the spell of the Red Shenron by turning Goku back into an adult.
With the Super Saiyan 4 at his disposal, there’s almost nothing that Goku can’t do. While Eis, Nuova, and Syn Shenron can hold their own against Super Saiyan 4 Goku, the only beings that truly surpass Goku are Omega Shenron and Super Saiyan 4 Gogeta and nobody else other than those two.