Ling Yao

Ling Yao is a Xingese character exclusive to the Manga and the 2nd Anime. He first appears in Chapter 32, in Rush Valley. He is a prince of the eastern nation of Xing. He is the essence of "Noblesse Oblige" - "privilege entails to responsibility". Though haughty, arrogant and ambitious, he cares deeply for his servants and people - a feeling that is returned, especially from his bodyguard, Ran Fan. Those outside his responsibilities are often less fortunate - as Ed learns from his habit of running up room service bills. His goal in life is to become immortal and become the emperor of his country of origin. He enjoys flirting with Winry and becomes a close friend of Ed's.

He instantly becomes a dedicated opponent of Führer King Bradley due to the Homunculus' belief that those in one's service who can no longer perform should be discarded. Ling is a devoted believer in fealty, that is, a King cannot exist without a people to support him. Bradley simply responds that a King is merely one who is powerful enough to compel obedience in others.

Ling leaves his country and heads to Amestris to find a way to become immortal, so he can gain the throne. In Xing, many families are striving for the position as emperor. The current emperor is ill, so if Ling can find a method of immortality and gives it to the emperor, he will be chosen as an heir (the emperor will retire eventually). Ling begins to look for the best lead he has: The Philosopher's Stone.

In The Belly of The Beast
During the fight with Gluttony and Envy outside of Dr. Knox's house, Gluttony eats Ling, Envy, and Ed, transporting them to the dark world that is Gluttony's belly. Ling and Ed try to make their way out, looking for any end to the abyss. They become extremely tired and hungry. Eventually, Envy catches up to them, and tells them that they are and are not in Gluttony's belly but are fact in the fake Door of Truth. After a brief moment of panic, Ed came to the subject of Ishbal which Envy revealed that he was the "soldier that shot and killed an Ishbalan child" thus creating the creating the civil war. Angry, after finding that Envy was the cause of also Winry's parent's death, gave Envy a punch which resulted to a fight when Envy decided that "they're going to die anyway". Envy reveals his true, monstrous form, and attacks them. Ed uses Envy as payment to open the Door of Truth and transport them to Father's hideout.

Immortality Obtained
After escaping Gluttony's belly, Ling, Ed, and Envy appear in Father's hideout. While Envy holds Ling and Ed down, Father approaches Ling and touches his own forehead, opening an eye on his head. A red blob, the Philosopher's Stone, seeps out of the eye on Father's head, and he drops it into one of Ling's wounds, telling him that Greed's position is currently empty. Inside Ling, his spirit and the invading spirit from the Stone are fighting. The spirit, who reveals himself as Greed, tells Ling that he wants his body and that he can offer him great power. Ling tells the spirit that he will do whatever it takes to gain power, and gives the spirit his body. Greed takes control of Ling's body.

Regain of Control
After meeting and killing Bido in Father's Lair, Ling is given an opening to start antagonizing Greed. The new Greed starts remembering friends from his first incarnation, and he starts freaking out. Ling says that the bonds between his family and him are too strong to be simply forgotten, and Greed cut down his soul's family with his own hands. Greed then visits and attacks Wrath, asking him why he can still remember them to which Wrath responds, "You're a fool, whose endless desire won't let him even discard the past!" Their fight ends soon after as Greed leaves; he then meets Ed and faints of hunger, thanking goodness to see a friend in a place like this. During Ling's control of his body, he tells Ed about Father planning to open the gate on the "promised day" and suggests that he and Al try getting their bodies back then. He asks about Ran Fan's condition, relieved to hear she's okay just before Greed takes over again. In the battle with Pride and Gluttony, Ling asks for control of his body to help fight Gluttony in the dark, and Greed obliges. He isn't disappointed as Ling deals a blow to Gluttony. Gluttony is angered and about to use his fake gate of truth when Ran Fan appears and stabs him in the head with her new automail; Ling is happy to see her again.