Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Hi, i have played kassa for long time now and this is the build that i use.
First, im not much of a writer so i will do this shortly :)
Simple :P harass with "Null Sphere" and hunt the last-hits from the creeps.
When the enemy/enemies go low on health dont be shy to initate/gank him/them. (i prefer: Go Bush, when they come on range use Exhaust and "Null Sphere" slow with "Force Pulse" and last hit him to death. if he gets to far, just use "NS" again to finish the kill)
By now you should have "Sorc.Shoes" even some AP if you have played well :P.
Again, make your enemies go low by harassing them with "Null Sphere", Initate with "Rift Walk" slow the target/targets with "Force Pulse" and finish the kill with "Rift Walk" + "NS" combo.
If the enemy ran away when u was making him go low, its not a problem coz you just got yourself some time to push a tower :D (if more enemies appear just repeat the above!)
At this point you should have everything to the Rylai's if you have played your game well and if your team is not full of ******s :D
Gather your team to mid and start pushing. remember you should NOT initiate (unless they are low and if they have not stacked Magic Resist coz Kassadin joined the game xD)
so let you tank do the task hes fit for :)
Again, Spam Null Sphere to the one with lowest Magic Resist/HP, Let your Tank initiate, use "NS" first, then "Rift Walk" + "Force Pulse". (remeber to silence their CC/healer) Repeat the combo and your done :D (TIP: you should try stack "Rift Walk" a little before your team is going to attack. so that your "RW" will do more DMG at the fight it self)
I prefer using Cleanse + Exhaust, coz Exhaust with Cripple will increase you DMG, Disable 1 of their melee champs and help you chase the enemy. Cleanse otherhand gives you a nice trick :D if u get CC:ed by anything: Cleanse + "Rift Walk" and you are at the safety again :). Teleport, is useful for Map control and the following :D.
A Good Defence TIP:
if your team is in bad position and you have lots of mana, try stacking "Rift Walk" at your base, run/Teleport to as close as you can and BOOM! RW!!! ****loads of DMG and a win on defence ;) (you can also try to gank someone with this style, but you will require a Sight Ward mostly :P)
Thnx, and Feedback is always welcome :D