In the movie Imaginarium of Dr.Parnassus, Percy and Anton are the assistants of Dr.Parnassus. They help in performing the show. As the movie progresses, we know that Percy is a former monk. He is confidant of Dr.Parnassus. He knows all the past life secrets of Parnassus.
When Dr.Parnassus tells the story of his life to his daughter, he reveals that he is an immortal and thousands of years old. In the flash back, he also tells a story of his bet with the Devil and how he attained immortality as bet. In those scenes, both Percy and Anton were shown as monks.
From character bio of Percy from IMDb,
Percy is a former monk and a long-time associate of Doctor Parnassus. When Satan came to the ancient monastery, Percy was there. Percy's job when we first meet him is as a carney for the Imaginarium. Actor, driver, babysitter, chaperone and the Jiminy Cricket-like conscience to the doctor, Percy is the backbone of the company.
We see Percy in the ending of the movie too.
We know that Dr. Parnassus was given immortality as a prize by the Devil in a wager. Did Percy also receive it?
If no, How did he gain immortality? How was he able to live through centuries?