With three dots in an Arcanum, a mage can add greater specificity when summoning a Supernal being.
All Supernal beings have a primary Arcanum, defined by their home Realm and the type of being (manifest or recondite).
They can have other Arcana, however, and a mage using this Attainment can narrow her summoning to Supernal beings with particular powers.
The mage spends one additional Mana during the summoning, and specifies a second Arcanum for the target Supernal being.
The primary Arcanum must remain one of the mage’s two Path Ruling Arcana.