Each Choir gets an affinity for 2 Influences. Each dot taken represents mastery over that Influence and controls the strength as well as the number of Invocations that the Angel knows from that Influence.
Unlike some power systems, Invocations can be learned in any order. The strength of each increases with growth of the Influence.
Certain virtue influences require that the character’s Halo be attuned a certain way. Innocence and Piety require Grace, Balance requires Balance, Corruption and Destruction require Maleficence.