If a damage buff or debuff (e.g. exhaust) is applied to a champion while they are channeling a spell (after they started the channeling) like ww' ult, kata's ult or fiddle's ult is the damage for that spell adjusted mid-channeling, or the buff/debuff has to be applied before they started channeling in order to take effect for that spell damage. What about spells that involve traveling projectiles like ez, ashe, draven, ziggs ulties? Or delayed spells like leona's ult?

I ask this as I mainly play support and when I see one of those ults, if I can't cc to stop them, I apply exhaust while they are channeling to lower their ult's damage for the remaining of the channel and I was just wondering if that works or I am just wasting my summoner's spell.

Also, as a side-note, how do you even test for something like this, or where do you get an (semi-)official answer?

  • 2
    Testing this would be easy. Make a custom game with a friend, start channeling the spell, look at the damage numbers, then apply Exhaust. Since the amount of damage is not random, you can determine with certainty whether or not Exhaust has an effect mid-channel.
    – Hackworth
    Feb 7, 2014 at 8:02
  • +1 very interesting question. I once saw that malzahars dot damage increased when i leveled up while it was the same dot on the target. I think it should be reducing damage when exhaust is cast on a Champion. I'll do some research when I find time.
    – Jutschge
    Feb 7, 2014 at 8:06
  • 2
    @Hackworth As a test, I suggest you try with FiddleStick, as he have a channel spell as soon as the beginning
    – Fabinout
    Feb 7, 2014 at 9:16
  • I know that fiddlesticks ult and drain are effected by exhaust (as long as the debuff is present) but the thing I'm not sure about is something like ashe/ez ult
    – Jutschge
    Feb 7, 2014 at 11:02

2 Answers 2


So I tried this stuff out a bit and I came to the following conclusion:

Every damage modification is applied Instantly

This means that the damage of a spell/dot/projectile is applied for the exact duration of the damage buff or debuff. The damage of an Ashe arrow for example is reduced only if she is exhausted on its impact. Dots work similar (I tried this with teemo shrooms): When someone walks into your shroom and you buy an item with ability power during the DOT time the dot will become stronger as soon as you have the item in your inventory (Same goes for leveling up a skill. I had this with malzahar e before). The dot damage is lowered for the duration of the exhaust on teemo and is also applied immediately. This also means that if an ezreal fires an ult for example it won't help if you exhaust him while he's channeling if the ult hits 4 seconds later.

Exhaust reduces damage while it's on the enemy. Not before and not after.

  • So all is as it should be. Cool. And thank you for this complete answer.
    – bolov
    Feb 7, 2014 at 17:37

Jutschge has the right answer but just to make a more general one.

Damage on abilities/auto attacks are calculated at the time the damage is taken, not when it is cast.

Channeling abilities are damage over time not continuous as they look so every tick of damage will go through all the math required to determine how much damage it will do (eg armor/mr, debuffs, pen etc).

Ex1) Jinx shoots her ult across the map, but you exhaust her before it hits the target, the damage will be reduced by 30%

Ex2) Lucian is channeling the culling(his ult), and you exhaust mid channel, all subsequent shots will have 30% reduced damage. (Note: the amount of shots based on attack speed will not change as this is calculated at the time of cast)


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