Etheric Light is an extremely valuable material, used for upgrading (or "Ascending") any Legendary weapon / armor to its maximum potential in "Year 1" of Destiny. As of writing, this means 365 ATK or +42 Light.
"Increases the [Attack/Defense] value of this [weapon/armor] to the highest available in Year 1."
Etheric Light can be acquired in several ways:
- Random reward from completing a Nightfall.
- Defeat a level 34 or 35 Arena Challenge in Prison of Elders.
- Reach The Lighthouse after a flawless 9-0 Trials passage in Trials of Osiris.
- Level 3 & 5 of Iron Banner. (not 100% confirmed)