C1: Vigilant Sentinel

After Illuga triggers a Geo-related Reaction on the field, he will regain 12 Elemental Energy. This effect can be triggered at most once every 15s.

C2: Elk With Fanged Antlers

When Elemental Burst Shadowless Reflection's Haunted Night's Oriole-Song effect is active, for every 7 stacks of Nightingale's Song consumed, Illuga will summon Aedon, dealing a single instance of Geo DMG to 1 nearby opponent. The DMG dealt is based on 400% of Illuga's Elemental Mastery and 200% of his DEF. This DMG is considered Elemental Burst DMG.

C3: Earthshaking Maw

Increases the Level of Elemental Burst Shadowless Reflection by 3.
Maximum upgrade level is 15.

C4: Solarhunting Wolf

When Elemental Burst Shadowless Reflection's Haunted Night's Oriole-Song effect is active, nearby active party members will have their DEF increased by 200.

C5: Hurricane Steed

Increases the Level of Elemental Skill Dawnbearing Songbird by 3.
Maximum upgrade level is 15.

C6: Nightmare Orioles

Enhances the Lightkeeper's Oath effect of the Ascension Talent Torchforger's Covenant: For Geo DMG dealt to opponents, CRIT Rate is increased by 10%, CRIT DMG is increased by 30%.

Moonsign: Ascendant Gleam:
When characters are affected by Lightkeeper's Oath, Elemental Mastery is increased by 80.
You must first unlock the Ascension Talent "Torchforger's Covenant."