In Persona 2: Eternal Punishment, he is a playable character, and like in the first game, his initial Persona is Aizen Myouou of the Hierophant Arcana.
A character sheet for Persona 2: Innocent Sin and its direct follow-up, Eternal Punishment. You Have Been …

Due to wiki policy, this page contains numerous unmarked spoilers. Sneak mentions that there are two people (a man and a woman) investigating the New World Order.

For a full index of characters from the Persona series, see this page.