Legend says that every 1000 years a Super Saiya-jin will arise. He will surpass all limits and have immeasurable power. Whoever achieves this level will be the most dominate being in the universe.|
Super Saiya-jin: |Son Goku| first turns Super Saiya-jin when he fights |Freeza|. |Freeza| had killed |Krillen| and |Son Goku's| got so angry and mad, knowing that he had to stop |Freeza| before more people got hurt.
|Trunks| is the next Super Saiya-jin that we see. |Trunks| came to the past using his time machine, thinking he could change the events in which led to his worlds demise. |Trunks| came right in time, to stop |Cyborg Freeza| from destroying the earth.
Super Saiya-jin "stage 2"(Ultra SS) : When |Son Goku| trained in the room of time during the Cell saga, he discovered that he can increase his power almost 3 times more than normal. But he realized that while this increase makes him more powerful, it also makes him slower. This is the major weakness which means that it is no good in battle.
Super Saiya-jin II : This level is first seen during the fight with |Cell|. |Cell| had pushed |Gohan| to where his anger and rage were unbearable. Then without warning |Gohan| had reached the next level, "Super Saiya-jin II". This was triggered when the |Cell Juniors| were beating the |Z Team| to the point where |Gohan| couldn't take it anymore. He wanted to save everyone from these monsters.
Super Saiya-jin III : Level 3 was first achieved by |Son Goku| during his fight with |Majin Buu|. During this process his saiyan hair grows longer and he loses his eyebrows. The bad part about this is that it takes your energy, so you can only be in this level for a brief period of time.
Super Saiya-jin IV: Level four is a complete transformer where their hair remains the same color, their bodies then get covered with ape-like hair and their eye color changes to yellow. There tail also grows back during this transformation, which means that they can turn into a Oozaru again. This is first achieved by |Son Goku| while fighting |Bebi| during the GT series.