Gluten Free is an achievement earned by defeating the encounter in the Nighthold instance, while having consumed a maximum of 20 Toxic Slices of cake, on Normal difficulty or higher.
Throughout the fight, Trilliax will spawn Toxic Slices of cake around the room of the encounter. Normally, these should be picked up to prevent raid-wide damage. For the achievement, however, you must ensure that, by the time Trilliax is defeated, the raid as a whole has consumed no more than 20 slices.
Note that the achievement is party-wide, meaning that no more than 20 slices must be consumed by the entire raid, as opposed to each individual player.
- Patch 7.0.3 (2016-07-19): Added.