Jay

It's compressed the same way...

Ultra Super Saiyan is compressed into a Super Saiyan 2.
How Freeza's bulky second form is supressed into his final form.
How Cell's bulky second form is supressed into his final form.


Basically the Super Saiyan Four transformation isn't really the fourth transformation in the Super Saiyan line, it's really just the Oozaru form taken and with the form's slow and clumsy nature (due to being a huge ape) is removed/adopted into a Saiyans' natural form.

Ssj4 is reached when a Saiyan controls himself or herself (although that's a different debate) while in the Super Saiyan Great Ape form, because of this... a Ssj4 is rational.

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