Who gave Father Cornello his Philosophers stone in Full Metal Alchemist?

Father Cornello never received a Philosopher's Stone in Fullmetal Alchemist. He was a homunculus created by Father, and his "stone" was actually a parasite that was implanted in him by Father. This parasite allowed Father to control Cornello and gave him his powers, making him seem like he had a Philosopher's Stone.

The true Philosopher's Stone in the series is an alchemical artifact created through the horrific transmutation of human souls. It's not something that's simply handed out or given, but rather something that's created through dark and unethical practices.