The skill evasion do the following:
Reduces the damage taken from area effect abilities by 1/2/3%
Does it reduce the damage from Karthus's Requiem ?
Requiem (Active): After channeling for 3 seconds, Karthus deals magic damage to all enemy champions regardless of the distance.
In the Wiki there is no example for Requiem.
There exist a various amount of AoE champion abilities, summoner
spells, and effect-granting items in the game and they can all be put
in the following categories:
Best Answer
Alright, The awesome FallenAngelEyes helped me do some science and here are the results:
With Evasion:
Without Evasion:
As you can see, Requiem does not get reduced by the Evasion mastery.
I ran the same set up for Karthus both times (gear, runes, and masteries).