The first Super Saiyan was the first Saiyan to ever become a Super Saiyan.
No one knows his real name not even him the Saiyans just called him Super Saiyan. In ancient scrolls it says he was so powerful that he could just power up and a whole planet would be destroyed. Even by the Z fighter standards he is super powerful.
No one opposed him until a magical wizard came up with a way to defeat him, he made a magical bottle which can trap anything and used it to trap him forever. Then the wizard built a tomb and sealed the bottle away so no one could ever find it again.
To this day the bottle still has him sealed for over 5,000,000 years.
The first Super Saiyan was born as a low-class Saiyan that everyone looked down on and made fun of, one day he and his crew members got a mission from the king at the time which was a simple mission, to destroy the planet Piza with his crew members. But the people of planet Piza the Pizans knew they were going to destroy the planet so they gathered every one to fight back as hard they could.
He was so mad the first Super Saiyan destroyed the whole planet plus a few other planets on his rampage. Drunk with power the first Super Saiyan became ruthless and wanted to rule the whole Universe, so he went back to planet Vegeta and started attacking his fellow Saiyan warriors and even killed the king.
Everyone was frightend with fear and didn't try to stop him cause he was so strong. This continued for about 4 years until a wizard made a magical bottle that can trap anything or anyone in it, so the wizard confronted the first Super Saiyan and opened the bottle which trapped him. Then the wizard made a tomb to seal the bottle away so he will never escape and cause any more trouble ever again. Years later he was found dead.