Manifest Charm of Shavarath, the Battleground
Charm
When you score a Critical Hit, you can expend the Charm (no action required) to deal an extra 10 damage of one of the types dealt by the attack.
Sources
Eberron: Forge of the Artificer p. 50
Charm
When you score a Critical Hit, you can expend the Charm (no action required) to deal an extra 10 damage of one of the types dealt by the attack.
Eberron: Forge of the Artificer p. 50