Android 8
First appearance: Muscle Tower arc
Android 8 is Dr. Gero's first android creation and easily the most human of the bunch—at least in personality. He looks kind of like Frankenstein's monster, which Goku immediately picked up on and started calling him "Eighter" (or "Hat-chan" in the original Japanese). The name stuck, and Eighter eventually adopted it as his own.
Despite being built as a weapon, Eighter turned out to be fundamentally gentle. When Murasaki tried forcing him to fight Goku inside Muscle Tower, he flat-out refused to kill him. Instead, he ended up helping Goku defeat General White and kick the Red Ribbon Army out of Jingle Village—the place where he decided to settle down and live peacefully.
The anime expanded his story a bit; he shows up again during the King Piccolo saga when Piccolo attacks Chow Castle (where Snow is staying). After that, he mostly fades into the background, making brief appearances in Dragon Ball Z and GT.
Content compiled by AnimeList.moe from publicly available sources.