Kassadin takes 15% reduced magic damage after magic resistance reductions have been applied. Kassadin converts each point of this ignored damage into 1% bonus attack speed for 4 seconds. This bonus attack speed stacks indefinitely, with the duration refreshing each time Kassadin takes magic damage.
Null Sphere
Range: 650
Cooldown: 9
Cost: 70 / 80 / 90 / 100 / 110 Mana
Active: Kassadin fires an ethereal bolt of void energy to a single target, dealing magic damage and silencing the target for a few seconds.
Active: Kassadin draws energy from spells cast in his vicinity, gaining a charge whenever a spell is cast near him, including his own spells. Upon reaching 6 charges, Kassadin can emit a pulse of void energy, dealing magic damage and slowing enemies in a cone in front of him for 3 seconds.
Active: Kassadin uses his void powers to blink to a nearby location, emitting a blast of void energy that deals magic damage to enemy units surrounding the destination area. Each subsequent Riftwalk in the next 8 seconds will cost 100 additional mana and will deal additional damage. The cost and damage increase can stack up to 10 times.
Cost of each nth Riftwalk (n x 100): 100 / 200 / 300 / 400 / 500 / 600 / 700 / 800 / 900 / 1000 / 1100
Total cost of using Riftwalk n times: 100 / 300 / 600 / 1000 / 1500 / 2100 / 2800 / 3600 / 4500 / 5500 / 6600 mana
3150 or 
790
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