The number of God's Holy Angels in Heaven is awsome, "numbering myriads of of myriads, thousands of thousands" (Rev 5:11; cf. Dan 7:10). Since the 4th century the number of angelic choirs has been reckoned at nine both in the Eastern and Western Christian traditions. Oftentimes, Our Heavenly Mother as the Queen of Holy Angels and Saints is brought into the center of this heavenly hierarchy. Indeed, the whole Family of Holy Angels and Saints continues to love, worship and serve the Most Holy Trinity without ceasing, forever and ever. What follows is quoted from the private revelations given to Magdalen of the Cross (Ancilla Domini, d. 1919), taken from the book entitled The Angels: Our God-Given Companions and Servants. This work was edited by Friederich von Lama in 1935, and translated from the German edition by Rev. Bede Dahmus (Washington, N.J.: The Blue Army, 1989). According to Magdalene, "all angels possess essentially the same happiness, because each one is perfectly happy. The choirs are really formed by the different degrees of the knowledge of God. St. Michael and St. Gabriel excel all other angels in this regard" (ibid, p. 6). "The angels serve us constantly. They expect no thanks and seldom get any" (ibid, p. 22)
The Guardian Angels/ "They exercise continual watchfulness over the souls committed to their care. Our guardian, who is our companion in life, will also be forever at our side in heaven. The joy of these angels is immeasurably increased when souls entrusted to their care enter heaven. The guardian angels of the lost souls are not deprived of their share of joy. Children have exceedingly lovely angels There is nothing more lovely than a guardian angel, nothing more gracious than the goodness of God, Who loves our souls so much that He assigns angels to watch over them, to guide and even to serve them. My most faithful friend, my holy angel, I greet you and I thank God that He made you so beautiful and so powerful" (ibid, pp. 7-8).
The Archangels/ "Veneration of the archangels brings such strength and consolation. St. Michael stands next to God The Father. He is clothed like a warrior, and his beauty is most majestic. St. Gabriel is the special messenger of The Holy Spirit, able to obtain for us a deep and sincere devotion to the Mother of God" (ibid, pp. 10-11). "St. Raphael is the patron of confession and penitents, the angel of consolation in earthly trials. The archangel of Fortitude is constantly at the side of certain souls, who are chosen to bear extraordinary sufferings" (ibid, pp. 14-15).
The Virtues/ "The Virtues are, as their name indicates, personified power or virtue. God assigns them to such persons who strive increasingly with all their soul to sanctify themselves. Some great sinners receive an angel after their conversion. For good thoughts alone do not make holy, one needs also strength to persevere and to accomplish this great task" (ibid, p. 18)
The Powers/ "With few exceptions they serve only the priests. The devil must give way before them. Priests should invoke these angels. Priests under the protection of the Powers have great influence over souls, and their work is very fruitful" (ibid, pp. 18-19)
The Principalities/ "Each parish has its own angel, who is taken from the choir of the Principalities. They kneel before the throne of God praying night and day for members of their parishes. They adore the Hidden God in the tabernacles, Who is almost forgotten" (ibid, p. 19)
The Dominions/ "We must pray to these angels for the spread of God's kingdom upon earth, for the conversion of heretics, for the return of lukewarm and fallen away Catholics" (ibid, p. 21).
The Thrones/ "Every diocese, very nation, every religious community has its own angel taken from this choir. Without ceasing they offer to God the prayers of the community" (ibid, p. 21).
The Cherubim/ "The Cherubim [pl. of Cherub] are the swords of God. Their garments shine with a pure brilliant light, and in general they resemble St. Michael. They Cherubim should be invoked" (ibid, p. 24)
The Seraphim/ "They were made for one thing alone --- to love the God of Love. Without ceasing they honor, praise, and love the most Blessed Trinity --- they can do nothing else" (ibid, p. 25).