Mark of Subversion question

[Lord Zado]

Mark of Subversion (availability)
Description: For 4-9 seconds, the next time target foe casts a spell on an ally, the spell fails and you steal 10-76 health from that foe.
Energy Cost: 25
Activation Time: 1 Second.
Recharge Time: 30 Seconds.
Linked Attribute: Blood Magic. Increases duration and health stolen.
Skill Type: Hex Spell.


I heard it costs 10 energy now. My question is: Does it only make the first spell fail or does every spell for the next 4-9 seconds fail? Similiar to backire.

[SkarjakTheFoul]

Backfire doesn't cancel spells, it only removes about a quarter of your life whenever you cast one.

Judging from the wording in the description, I would say it probably only affect the next spell. First, because it would be overpowered otherwise and second, because if not it would say "every time" instead of "the next time".