Devo wields the Stand of misfortune, Ebony Devil. He was already famous as an assassin before he was recruited by Dio Brando.
Devo fought Polnareff in a hotel room at Singapore. He lured Polnareff to hit him to activate his Stand before escaping through the window. Ebony Devil then stayed behind to fight against Polnareff. Eventually Polnareff managed to defeat it.
Ebony Devil inhabits the strange doll that Devo carries around. It is powered by Devo's hate for his enemy. Ebony Devil wields a variety of weapons and attacks his target mercilessly.