Originally Posted by The Green Dragon

I reckon if Goku (Being a pure blooded saiyan) builds up over time he could achieve Mastered Super Saiyan 2 or Mastered Super Saiyan 4, if he tries to stay in Ssj2 or Ssj4 for as long as possible during his training.

The reason I personally don't think he can achieve Mastered Super Saiyan 3 that easily is that Ssj3 is the form that put Goku under the most strain and consumed the most energy... making it almost impossible to hold it for too long if not in the Other World.

If considering Ssj4 as more of a Controlled Oozaru form than a Super Saiyan form (i.e. on a different scale to Ssj1, Ssj2 and Ssj3), Super Saiyan 3 is apparently a Super Saiyan's complete limit. Probably making Ascended Super Saiyan 3 impossible.

Ssj4 was easier for Goku to maintain than Ssj3 (every 2 or 3 transformations achieved seem to remove a heavy weakness the previous form suffered from: Ussj's decrease in speed due to high muscle mass increase, and Ssj3's inability to maintain the form for too long)


And yeah Ultra Super Saiyan (Ussj) is the form Trunks took to beat on Cell, but due to the muscle mass increase it made Cell faster. Ultra Super Saiyan is a fan term, the more accurate term is Super Saiyan 3rd Grade.