From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Ao (according to a special issue of V Jump) was the youngest of the brothers. He was defeated by Goku, as were the rest of his brothers. He speaks in a notably different accent than the other brothers. He wielded a kusarigama. Ao's name is a pun on the word Ao, or Blue in English.
Murasaki's Brothers were part of a quintuplet ninja group who tried to stop Son Goku from reaching the top of Muscle Tower. They each wielded a different weapon. At first, it seemed that Murasaki 1 could split into five people. In reality, the other four were his identical brothers. They distracted Goku while Murasaki 1 escaped. Goku managed to defeat all of them with punches, kicks, and the last one with a Power Pole whack to the head.