You are probably thinking of Origen of Alexandria. Origen was a 3rd century philosopher and theologian whose ideas were very influential; he is often condidered the first great Christian philosopher. However, he is not considered a saint by the Catholics or any other modern branch of Christianity, due to some of his decidedly heterodox ideas.

The idea of the devil's salvation is a logical implication of Origen's concept of apocastasis, a radical version universal salvation meaning eventual salvation, restoration and glorification of all that exists. While none of his preserved writings explicitly claim that this includes the devil, many ancient critics allege that Origen taught that. (And it should be noted that some theologians who have an idea of apocastasis do not believe in the salvation of the devil.)

You are probably thinking of Origen of Alexandria. Origen was a 3rd century philosopher and theologian whose ideas were very influential; he is often condidered the first great Christian philosopher. However, he is not considered a saint by the Catholics or any other modern branch of Christianity, due to some of his decidedly heterodox ideas.

The idea of the devil's salvation is a logical implication of Origen's concept of apocatastasis, a radical version universal salvation meaning eventual salvation, restoration and glorification of all that exists. While none of his preserved writings explicitly claim that this includes the devil, many ancient critics allege that Origen taught that. (And it should be noted that some theologians who have an idea of apocatastasis do not believe in the salvation of the devil.)