A part of the Hymns talent tree.

 Hymn of Moonlight: sustained, 20 negative, 12 cooldown, drains (8, 7, 6, 5, 4) negative energy per attack, 5 range, instant cast
 Hits up to (talent, rounded down) enemies for (0.37 * [7 + spellpower] * talent modifier) rescaled darkness damage each.