The three persons of the Trinity are not roles. Someone explained this to me by saying that the nature define WHAT you are, the person defines WHO you are.
So if I walked in the room you could say
WHAT are you - a human being
WHO are you - winsome
The WHAT of God is his divine nature - only one divine nature
The WHO of God is Father, Son or Spirit.
They are defined by RELATIONSHIP not by role.
The Athanaseain Creed defines it well:
Athanasian Creed
P: Whoever wills to be saved must before all else hold fast to the Catholic faith. All: Unless one keeps this faith whole and untarnished, without doubt he will perish forever.
P: Now this is the Catholic faith: that we worship one God in Trinity, and Trinity in unity;
All: Neither confusing the Persons one with the other, nor making a distinction in their nature.
P: For the Father is a distinct Person; and so is the Son; and so is the Holy Spirit.
All: Yet the Father, Son, and Holy Spirit possess one Godhead, co-equal glory, co-eternal majesty.
P: As the Father is, so is the Son, so also is the Holy Spirit.
All: The Father is uncreated, the Son is uncreated, the Holy Spirit is uncreated.
P: The Father is infinite, the Son is infinite, the Holy Spirit is infinite.
All: The Father is eternal, the Son is eternal, the Holy Spirit is eternal.
P: Yet they are not three eternals, but one eternal God.
All: Even as they are not three uncreated, or three infinities, but one uncreated and one infinite God.
P: So likewise the Father is almighty, the Son is almighty, the Holy Spirit is almighty.
All: Yet they are not three almighties, but they are the one Almighty.
P: Thus the Father is God, the Son is God, the Holy Spirit is God.
All: Yet they are not three gods, but one God.
P: Thus the Father is Lord, the Son is Lord, the Holy Spirit is Lord.
All: Yet there are not three lords, but one Lord.
P: For just as Christian truth compels us to profess that each Person is individually God and Lord, so does the Catholic religion forbid us to hold that there are three gods or lords.
All: The Father was not made by any power; He was neither created nor begotten.
P: The Son is from the Father alone, neither created nor made, but begotten.
All: The Holy Spirit is from the Father and the Son, neither made nor created nor begotten, but He proceeds.
P: So there is one Father, not three; one Son, not three; one Holy Spirit, not three.
All: And in this Trinity one Person is not earlier or later, nor is one greater or less; but all three Persons are co-eternal and co-equal.
P: In every way, then, as already affirmed, unity in Trinity and Trinity in unity is to be worshiped.
All: Whoever, then, wills to be saved must assent to this doctrine of the Blessed Trinity.
P: But it is necessary for everlasting salvation that one also firmly believe in the incarnation of our Lord Jesus Christ.
All: True faith, then, requires us to believe and profess that our Lord Jesus Christ, the Son of God, is both God and man.
P: He is God, begotten of the substance of the Father from eternity; He is man, born in time of the substance of His Mother.
All: He is perfect God, and perfect man subsisting in a rational soul and a human body.
P: He is equal to the Father in His divine nature, but less than the Father in His human nature as such.
All: And though He is God and man, yet He is the one Christ, not two;
P: One, however, not by any change of divinity into flesh, but by the act of God assuming a human nature.
All: He is one only, not by a mixture of substance, but by the oneness of His Person.
P: For, somewhat as the rational soul and the body compose one man, so Christ is one Person who is both God and man;
All: Who suffered for our salvation, who descended into hell, who rose again the third day from the dead;
P: Who ascended into heaven, and sits at the right hand of God the Father almighty, from there He shall come to judge both the living and the dead.
All: At His coming all men shall rise again in their bodies, and shall give an account of their works.
P: And those who have done good shall enter into everlasting life, but those who have done evil into everlasting fire.
All: All this is Catholic faith, and unless one believes it truly and firmly one cannot be saved.
P: Glory be to the Father
All: As it was in the beginning.
Sorry that's a bit of a long post