In the anime, Wrath is the second youngest Homunculus. With the appearance of a seven to eleven year-old child, he has the ability to fuse his body's form with other objects, whether or not the objects are organic. He possesses the exceptional ability to perform alchemy (unlike the other Homunculi), and is unique even among most alchemists in that he can transmute without a transmutation circle. He can do this because of his right arm and left leg, which originally belonged to Edward Elric (who lost the limbs in an attempt to bring his mother back to life, which resulted in Sloth, and in affixing his brother's soul to an object). In one instance, Wrath accidentally fused himself to the bed on which he was lying, combining his organic form with that of the bed's wooden frame and cloth sheets. Later he was able to fuse himself with Sloth. He has the ability to stretch his Homunculus limbs to great lengths, at which time his limbs take on a blue color, and appear similar to a large mass of muscle fibers. Wrath's alchemy stems from the fact that his limbs were once part of a being with a soul who never died (i.e., Ed). However, as they are only a small part of the being, his alchemy must, like the alchemy-like powers of the other homunculi, be focused around himself. He has performed transmutations on other objects without fusing himself, such as when he mirrored Ed's trademark lance, but these transmutations are simple. More complex alchemy requires him to fuse himself with the object or fuse with the transmutation circle itself, as he did when he activated the Flamel array he used to make Lust vomit up her red stone. However, Wrath lacks the ability to create such stones for himself. Wrath is also one of the few Homunculi who ages, growing from a deformed baby to a child in the series and from a child to a young teenager in Conquerer of Shamballa. Wrath's tattoo is on the sole of his right foot.
Wrath was created when Izumi Curtis attempted to transmute her dead child on Yok Island. The result was a Homunculus with its typical inhuman appearance when immature. Izumi sent it back into the Gate where Wrath remained, aging there in the process. When Edward attempted to revive his mother, Wrath took possession of his lost limbs within the gate. The limbs eventually gave Wrath the power to force open the gate and come back to Yok Island where he lived until he was discovered.
After being discovered by the Elrics on the Island, he was taken to the house of Izumi Curtis. He eventually ran away and his existence became known to Envy, the military, and Greed. Envy eventually made contact with Wrath and provided him with incomplete Philosopher’s Stones. On consuming the stones, Wrath became a mature Homunculus. The stones' power and Envy's words changed his demeanor from that of an innocent child's to the total incarnation of his cardinal sin, full of raw hatred and anger--especially at his master for creating him. Wrath was encouraged by Envy to hate Edward and attempted to take his body, so that he could absorb it and become completely human (but without a soul of his own Wrath would only be as human as Pride).
Unlike the other Homunculi, Wrath was created directly from the materials of the human that was being transmuted. Because of this, Wrath did not share the weakness of the other Homunculi because the remains of the original body no longer existed. However, Wrath had other weaknesses: a deep and paralyzing phobia at the sound of a wailing baby and that of the Gate itself. The human nature of his arm and leg were also a weakness. Although Wrath was affectionate towards Izumi at first, after meeting Envy, and typical of the other Homunculi, Wrath rejected his creator. He eventually adopted Sloth as his mother, probably as part of a delusion that he could become Edward by taking things that belonged to him.
After Sloth's death, Wrath was inconsolable, and started talking about using the Philosopher's Stone to revive her. However, Dante had Envy beat Wrath for it and the fearful child finally came to understand the truth about his relations to them. Wrath then attempted to revive Sloth himself, forcing Dante to summon the Gate, which dragged in the human parts of Wrath before Edward emerged from it. This is similar to the punishment described in Dante's Inferno for the sin of Wrath: being dismembered alive. Wrath could not replace his human limbs with non-human ones, presumably because his original arm and leg sank into his body when he asborbed the human limbs, which were susceptible to prolonged injury Winry eventually fitted Wrath with automail similar to Edward's.
His whereabouts for the next two years are unknown, though he did resurface to visit his creator's tomb, but appears as a shell of his former self: likely because he has no red stones to consume and accepting who he was after the events of the finale. He guided Alphonse Elric through the underground city to find and open the Gate. Gluttony, now a huge and mindless monster ravenous with hunger, attacks, attempting to devour Wrath. After Gluttony expels some red stone material, Wrath consumes it and regains considerable strength. With his new power Wrath is able to hold Gluttony off for a short while, but then purposefully smashes his own automail in the center of a Gate opening transmutation circle, allowing Gluttony to take him into his jaws. He then screams for Al to use both he and Gluttony as Equivalent Exchange to open the portal. Al is wary of sacrificing Wrath, but is assured by the homunculus that this was the very reason he brought Al there in the first place. Al forcefully carries out his request and transmutes the Gate, destroying both Wrath and Gluttony in the process. Upon his redemption Wrath - in his untainted form with all limbs - is seen standing in front of the doors of the Gate, which open with Izumi there to greet him. Reunited at last, the two disappear into the hereafter together.