Gouki and his brother Gouken were students of Goutetsu. Goutetsu taught a life-threatening martial art called Ansatsuken (Assassin Fist), which incorporates elements of karate, judo, taekwondo, and koppo. He also taught Shun Goku Satsu (literally Instant Hell Murder or The Raging Demon), a death technique which, although incredibly powerful, puts the user in considerable danger.

As the brothers progressed under Goutetsu's tutelage, a dispute arose on the true nature of Ansatsuken and the path to master it. Gouken, unable to accept the violent nature of Ansatsuken, left Goutetsu to begin his own dojo. Gouki continued Goutetsu's teachings and vowed to use Ansatsuken as it was intended.

In order to learn Shun Goku Satsu, Gouki embraced the principle of Satsui no Hadou or (The Surge of the Intent to Murder/Murderous Intent). Through Satsui no Hadou, Gouki was forced to give up any compassion he held towards other human beings. In addition, Gouki realized his limits as a martial artist could be expanded, and left Goutetsu's guidance to train alone on an island.

His return marked the end for Goutetsu - Gouki demonstrated his strength by killing his former master with Shun Goku Satsu. Goutetsu fell with an inner joy, realizing his pupil was attempting to master Ansatsuken. Gouki removed the beaded necklace from Goutetsu's neck and placed it around his own. The following day Gouki challenged and fought his brother. With Gouken gaining the upper hand, Gouki was eventually struck down. Gouki requested death in defeat, however his brother was unable to kill his own kin. Gouki , sensing weakness, mocked Gouken and struck with Shun Goku Satsu. The dojo was filled with a burst of white light and Gouken was killed. Ken saw the flash as he was returning from the U.S. Martial Arts tournament. Rushing to the dojo to find it in shambles and his master dead, an enraged Ken ran into the surrounding woods searching for the killer. Gouki easily defeated Ken and disappeared. Gouken's other student Ryu soon learned of his master's death and began to search for Gouki.