Philosopher's stone
Gluttony is the failed product of Father's attempts to create a Gate of Truth. When activating this imperfect portal, Gluttony's stomach opens up, revealing a bestial counter-version of the Eye of Providence at its center. His ribs spread out to act as a border for the gate and double as large extensible teeth that can consume everything in his corrupt Eye's field of vision in an instant. Anything Gluttony consumes is transported to a stagnant, hellish dimension, which is filled with an endless repugnant sea of blood, and is littered with victims and artifacts from centuries before the start of the series. In the ensuing battles after Lust's death, the energy in Gluttony's Philosopher's Stone is exhausted to the point of nearly dying. Father later restores Gluttony and sends him with Pride to capture the Elrics. Gluttony is repeatedly killed by Greed and Lan Fan, which causes Pride to devour Gluttony in order to gain his abilities while replenishing his own Philosopher's stone.