Sirensong, in addition to 5%Lifesteal also has an Unique Active which, for 6 seconds, on hit with an basic attack, steals 60 Max Movement Speed from targets for 3 seconds.
Stacks with other movement speed boosts and slows.
This card only works with corruption heroes, thankfully, most assasin heroes are corruption type. This card is primarily intend for any corruption hero that is struggling in the gank department. This card is viable for Kalari, Countess, Grux, and Serath