Android 8 is an android created by Dr. Gero. He was intended to serve in the Red Ribbon army, however he attains a tranquil nature.
After defeating Ninja Murasaki, Goku is introduced to Android 8, courtesy of Murosaki. Murosaki intended to release him in order to destroy Goku. As it turns out, Android 8 refuses to battle Goku and is threatened by Murosaki, stating that he will detonate him using a remote control. Goku proceeds to knock the remote out of Murosaki's hand. He then knocks out Ninja Murosaki himself. Goku then nicknames Android 8 "Eighter" and the two of them become friends. When General White gives Android 8 an ultimatum : kill Goku or the Jungle Village Chief will be shot, Goku decides to do his best to defuse the situation by turning around and allowing himself to be shot, void of opposition. After witnessing Goku get injured, Android 8 is enraged. He punches White clean through Muscle Tower's uppermost window. Android 8 then proceeds to destroy Muscle Tower itself. After destroying the Army Contingent in Jingle Village, Android 8 reveals that he found and hid the Dragon Ball that the Red Ribbon Army was looking for. He did this because he knew that the Red Ribbon Army had intended to kill the villagers once it was found. After hearing this, the head of the village invites Android 8 to live with them, which he happily accepts. Before Goku leaves the village, Goku, Android 8, and Suno head over to where Dr. Flappe resides, an expert in machines.They do this in order to remove the Android Bomb implanted within Android 8's chest. After a short confrontation with Ninja Murosaki, Dr. Flappe successfully removes the bomb. Android 8 is later seen during the King Piccolo Saga of Dragon Ball when he goes to rescue Suno after she falls victim to the assault of King Piccolo on King Castle.
Android 8 makes some cameo appearances throughout Dragon Ball Z, the most significant of which occurs during the Kid Buu Saga when Goku is forming a Spirit Bomb. Android 8 along with his fellow villagers supplies Goku with their energy in order to defeat Kid Buu.
Android 8 is also briefly seen during the 40th episode of Dragon Ball GT where he is transported off of Earth by Goku before it explodes due to the Black Star Dragon Balls.