Summary
Sloth serves as the fifth Homunculus brought into existence by Father. Resembling a colossal, muscular man with limited mental acuity, he dedicates the majority of the narrative to excavating the vast subterranean tunnel network that constitutes the transmutation circle spanning the nation. Hints from dialogue between Greed and Lust suggest this labor has persisted for over a century. Naturally, Sloth is desperate to complete his task so he may finally rest. In the original anime adaptation, Sloth was accidentally formed during the failed human transmutation performed by Ed and Al, manifesting in the appearance of their mother, a stark contrast to his portrayal in Fullmetal Alchemist: Brotherhood. Once the tunnels are finished, Sloth is summoned to Central on the Promised Day with orders to eliminate anyone threatening Father’s scheme, particularly General Armstrong. Although she resists with assistance from her brother, their strategy falters with the arrival of Mannequin Soldiers and Central forces. Sloth then unveils his Homunculus capability for supersonic movement, nearly killing the siblings before Izumi and Sig Curtis intervene to help destroy Sloth's Philosopher's Stone.
