Boy II Man

"I've already absorbed one-third of your Stand! I beat you once at janken. That means one-third is mine! I can control one-third of Heaven's Door!"

- Ken Oyanagi

Boy II Man (ボーイ・II・マン) is the Stand of Ken Oyanagi, featured in the fourth part of the JoJo's Bizarre Adventure series, Diamond is Unbreakable.

Its power allows it to steal the energy from anyone who loses to its user in a game of.

Appearance
Boy II Man is a muscular humanoid spirit clad in riveted armor with a pointed helmet resembling those worn by medieval knights. The Stand always manifests itself coming out of the hole in Ken's cheek, made by the Bow and Arrow.

In the anime, Boy II Man is shown to have no lower half, instead being presented with a wispy or cloud-like protrusion instead of legs, similar to a genie.

Its design such as the rows of rivets and the mask over its mouth is heavily inspired by the robots from one of 's mangas.

Abilities
Boy II Man is a Stand with no shown combat ability, and is centered around the game of rock-paper-scissors but is surprisingly threatening because of its ability to steal someone's energy through a simple game.

Energy Theft
Boy II Man's power is to steal the energy of an opponent whenever Ken wins a game of (RPS).

If Ken proposes to play a game of RPS and the opponent formally accepts, Boy II Man sets up a best-of-five game of RPS with the following rules: When Ken wins a round, Boy II Man appears to take away one third of the opponent's Stand power. For instance, it literally tears away a third of Heaven's Door body and absorbs it inside the hole on Ken's cheek. Rohan is unharmed by the energy theft, but the corresponding body part begins to tire and falls under the control of Ken who can move it as he wants.
 * A draw nulls the round and it has to be played again until someone wins.
 * Every time Ken wins a round, he takes a third of his opponent's energy and Stand.
 * If the opponent manages to win three times, their energy is returned and the game ends.

Moreover, Ken also begins to acquire the same power as the Stand it is stealing. It allows him to undo one of Rohan's command and resume his game. If Ken wins three times, Yoshihiro claims that he will gain the power of the stolen Stand forever and be free to use it in conjunction with Boy II Man.

Boy II Man possesses an inherent weakness in that people are allowed to cheat during the game, enabling Rohan to regain his Heaven's Door during his first gain by using the invisible Shizuka to force Ken's scissors hand into a rock hand.