Don't need team... got me.—Yang's bio.
Yin Yang is the martial art specialist of the The Expendables. A shaolin, honorable, but rejects killing in “gruesome” ways. His Weapons of Choice are Shurikens and/or his enemies' weaknesses. Yin Yang is a Chinese-American, hoping to live his own version of the American dream.
A Chinese-American martial arts master, Yin Yang's work with the Expendables is fueled by his desire to fulfill the American Dream... and make money.
Yin Yang aids the team in freeing hostages from Somalian Pirates which becomes a success. However, a moral dilemma forces Yin Yang to stop Gunner Jensen from hanging a pirate. Barney Ross save Yin Yang from the skirmish.
Later, Yin Yang is briefed about a new job in Vilena where Hale Caesar playfully teases him about his height and Toll Road lectures everyone about the "ear" much to Yin Yang's annoyance. During the mission he asked for a raised to support his son surprising everyone that he has a family, which they rightfully don't believe he has.
After Barney Ross and Lee Christmas return from the recon, Barney Ross pulls out of the job due to the danger, much to Yin Yang's sorrow as he wanted the money. When Barney Ross decides to go in alone to save Sandra, Yin Yang goes with him. On the way to the airport, Yin Yang complains that he needs more money since he "works harder" due to his size and he admits that he has no family. A vengeful Gunner Jensen then jumps the duo and Yin Yang combats Gunner Jensen. Yin Yang gets the advantage at first but Gunner Jensen turns the tables at the last minute and attempts to impale Yin Yang on a pipe, but Barney Ross shoots Gunner Jensen. As the whole group agrees to aid them, Yin Yang defends that "(Yang) would have win" against Gunner Jensen.
On Vilena, Yin Yang sets explosives all over the palace and aids Lee in killing The Brit.
Rescuing the billionaire
See you later alligator.—Yin Yang's final words to Gunner before leaving
Yin Yang joins his fellow Expendables in the mission to rescue a Chinese billionaire. Paired up with Gunner Jensen they and the other Expendables kill every solider in sight. Later Yin Yang fights hordes of soldiers in hand to hand combat mostly using frying pans. After defeating the soldiers he rejoins the Expendables and they escape with the billionaire. Later on the plane Yin Yang poses for a picture and departs the Expendables with the billionaire and jumps out of the plane escorting the billionaire back to China.
Old Blood vs New Blood
In The Expendables 3, he is not seems through out the entire film until in the final battle. Where he and Trench Mauser escorting Max Drummer to the Albania for the confrontation with Conrad Stonebanks. Most of the time, he is fending off Conrad Stonebanks forces for rescuing the whole team fighting alongside with Trench Mauser in the chopper. At the end, he with the entire team celebrate at the Bar for the victory of Mission Successful. He and Trench Mauser made their "bro-romance" be well-established. 
The Expendables 4
Yin Yang seems to go by a sense of honor, not wanting to kill people in gruesome manners. Yin Yang also has a persecution complex about his height. Due to his height, he thinks he works twice as hard since he’s the shortest. Yin Yang is a habitual liar to serve personal profit, as he pretended he had a wife and son hoping it would sway Barney Ross to give him one.
It was implied that Yin Yang did not get along with Gunner Jensen. Later in the Expendables it appeared that the two were now getting along. Though it was implied in the second that Gunner Jensen still picks on him but that they maintain a good relationship despite their differences. he will maintain his personality on the manga series, he will be one of the people that will keep Gunner in check.