When you sustain Hunger of Hadar, it doesn't say "The Zone Persists" as many powers do, but it's sustain effect is dependant on the zone being there. Does the zone persist? If so does it continue to do the 2D10 damage?
Hunger of Hadar Warlock Attack 5
You create a zone of complete, impermeable darkness filled with flying, fluttering, fanged shadows. The shadows rend at the very life force of creatures caught within.
DailyArcane, Implement, Necrotic, Zone![]()
Standard Action Area burst 1 within 10 squares
Effect: The burst creates a zone of darkness until the end of your next turn, blocking line of sight. Creatures that enter the zone or start their turns there take 2d10 necrotic damage.
Sustain Minor: When you sustain the power, you make a secondary attack.
Secondary Target: Each creature within the zone
Secondary Attack: Constitution vs. Fortitude
Hit: 1d6 + Constitution modifier necrotic damage.