Sustain

Similar to Concentration, a power can have the duration "sustained". What this does and doesn't mean:

• A sustained spell does not use your concentration slot.
• It may use the target's concentration slot if cast on someone else (per the power's description).
• It may also require spending a certain action each round to maintain, as specified in the power's description.
• Taking damage, losing consciousness, etc does not end a sustained spell directly, although it may prevent you from taking the required action to maintain it.
• By default, all sustained spells end with a long rest, or if you die.