Gokuu was an all around good guy, unlike Vejita which you will find out later. He always fought on the side of good, and being a Saiyajin he was also very strong. So he mastered the most difficult of techniques including, Kaiooken, the Kamehameha, the Genki Dama, and Super Saiyajin technique. Note that Goku was the first to become Super Saiyajin out of all the others. He was also the first to reach SSJ 3 and 4 therefore being the strongest for nearly the entire time.
Techniques
Japanese (English)
-Genki Dama (Spirit Bomb)
-Taiyoken (Solar Flare)
-Kaiooken (Kaioken)
-Supaa Saiyajin (Super Saiyan)
-Kamehameha (same)
-Instant Teleportation