Greed (グリード, Gurīdo), the "Ultimate Shield", craves money, women, and other worldly possessions above all else. Because of this he betrays the homunculi in both the anime and the manga, as working for them would deprive him of his greedy desires. He is able to rearrange the carbon molecules in his body to create a shield that coats his body and is as hard as diamond. Greed is introduced when he sends some of his chimera subordinates to capture Alphonse Elric. The State Military soon raids their location to rescue Al, and Greed's fate from that point further differs between adaptions.

In the manga, Greed is repeatedly killed by Wrath, tiring him out and allowing him to be taken back to Father. Unwilling to rejoin them, Greed is melted down and Father consumes his Philosopher's Stone. Later, Lin Yao offers to become a new Greed in his search for immortality. Greed is given complete control of Lin's body, though Lin constantly fights him to gain dominance. Though this Greed initially has no recollections of his actions as the former Greed, his killing of Bido brings back memories of all his loyal subordinates. Angry with Wrath for killing his "possessions" and further provoked by Lin, the new Greed defects from the homunculi, eventually letting Edward Elric join him. As the other homunculi's ranks start to thin, Greed abandons his new subordinates so that he can kill Father and take over the country.

In the anime Greed escapes the raid and flees to Dante's mansion. Dante, having created Greed when she tried to revive her dead lover, is as a result in the possession of the skull from his original body. This leaves him severely weakened and he is killed by Edward Elric soon afterwards.

Source: Wikipedia