The question most commonly used when inquiring about Deacons in the Catholic Church is "What is a Deacon?, or What exactly is a Deacon?" The more appropriate question really is "Who is a Deacon? A Deacon is not a thing, an object, or merely a function, role, or title, but a human being who has responded to a call from God for a life of service in the Church. He recevies through the Sacrament of Ordination and indullible imprint on the soul and a specific sacramental grace which configures him to Christ, who made himself deacon or servant of all.
The Basic Norms for the Formation of Permanent Deacons #5 states "the theological identity of a deacon as stated in the Dogmatic Constitution on the Church (Lumen Gentium) #29,(7) "as a participation in the one ecclesiastical ministry, he is a specific sacramental sign, in the Church, of Christ the servant."