the Void Walker
Assassin MageCutting a burning swath through the darkest places of the world, Kassadin knows his days are numbered. A widely traveled Shuriman guide and adventurer, he had chosen to raise a family among the peaceful southern tribes—until the day his village was consumed by the Void. He vowed vengeance, combining a number of arcane artifacts and forbidden technologies for the struggle ahead. Finally, Kassadin set out for the wastelands of Icathia, ready to face any monstrous Void-construct in his search for their self-proclaimed prophet, Malzahar.
Void Stone (KassadinP)
Kassadin takes 15% reduced magic damage and ignores unit collision.
Null Sphere (KassadinQ)
Kassadin fires an orb of void energy at a target, dealing damage and interrupting channels. The excess energy forms around himself, granting a temporary shield that absorbs magic damage.
Nether Blade (KassadinW)
Passive: Kassadin's basic attacks deal bonus magic damage. Active: Kassadin's next basic attack deals significant bonus magic damage and restores Mana.
Force Pulse (KassadinE)
Kassadin draws energy from spells cast in his vicinity. Upon charging up, Kassadin can use Force Pulse to damage and slow enemies in a cone in front of him.
Riftwalk (KassadinR)
Kassadin teleports to a nearby location dealing damage to nearby enemy units. Multiple Riftwalks in a short period of time cost additional Mana but also deal additional damage.
It takes 6 spell casts for Kassadin's slow, Force Pulse, to become castable. If he levels up that ability, judiciously use your own skills while laning against him.
Kassadin deals mostly magic damage. If he's doing well consider buying magic resist items like Mercury's Treads and Banshee's Veil.
Each time Kassadin consecutively uses Riftwalk, he pays more and more mana. Keep this in mind as you chase him.