In League of Legends, Rylai's Crystal Scepter seems like a great take for Vladimir, giving a large boost in both AP and health. But which of Vlad's abilities trigger the Scepter's slow effect? In particular I want to know if it works with Transfusion (Q).
Rylai's is a decent pick on Vladimir, but ever since his nerf from his passive on the conversion of HP into AP I don't take it anymore and just focus on pure AP item like Rabadon's Deathcap.
But to answer the question, all of Vladimir's spells would proc Rylai's Unique ability, UNIQUE: Your spell damage slows the target's movement speed by 35% for 1.5 seconds (15% for multi-target spells and damage-over-time spells).
Which means, your transfusion would slow the target by 35% but the rest of your abilities since they are all AoE, multi-targeting spells, would only slow by 15%.
One of the notes on Vlad's League of Legends wiki page indicates that Transfusion only slows 15% (possibly because it also targets Vlad?).
I don't know if that is accurate, however.
Rylai's on Vlad works, but will only use the 15% slow, even for Transfusion (a single target nuke). Riot has said this is for balance purposes because of the cooldown on transfusion (Cassiopeia's twin fang also only applies 15% for the same reason).
I can't find the source for it, but I don't believe slows from the same characters don't stack, and slows from different characters apply (first slow + 60% second slow).
Just for clarification, when Vlad was initially released his Q (Transfusion) only applied a 15% slow from Rylai's Crystal Scepter. This was a decision made and applied to the ability due to it's incredibly low cool-down and therefore possibility of a permanent slow on an enemy champion.
As of the Riven Patch (184.108.40.206, Sept 14 2011) his Q applies the full 35% slow of Rylai's.