Hello, my league name is Bright Sun and I've been a Kassadin main in ranked during season 7, and I abused his power to climb to Platinum with a whopping winrate over 70%. Kassadin is a highly mobile AP assassin that can carry a game in almost any circumstances (unless they have a fed tank, then gg). Kassadin can be built in a few variations that most other AP champions cannot do. For example, Kassadin can build an Iceborn Gauntlet if he is against heavy AD, and still oneshot the squishies. Also, Kassadin is very easy to snowball with, roaming constantly and getting kills around the map, turning a close game into a stomp in a matter of plays. This guide will help you get through laning phase strong and take the enemy team to the dumpster. As always, leave a comment if I left out anything crucial to this guide and if you have any other suggestions to improve this guide.

This guide will give you the rundown on the important items to buy in what situations, and what to do during laning phase. Also, it will show what to do in certain situations and some other tips and tricks. Kassadin is most well known for being one of the most mobile champs in the game provided he has enough mana. Once you get your ult, Riftwalk, escaping ganks and roaming wherever you want is a breeze.

Flash

Flash is the best summoner spell, self-explanatory.

Ghost

Teleport is quite useful to Kassadin, for either getting back to lane or teleporting bot lane for a gank.

Ignite

Only take ignite if you know you can bully the enemy laner hard and possibly get an early kill to help snowball the game.

Summon Aery

After playing KASSAWINNN during the preseason, it has become clear that Summon Aery is indeed the best rune to take, to survive the harsh mid lane matchups.

Manaflow Band

Kassadin struggles to farm against hard AD matchups, having to expend most of his mana on just clearing the waves. Manaflow Band helps so much, giving you a chance to get into the mid game.

Transcendence

More CDR always helps, especially because most Kassadin builds only reach up to 30% cdr in favor of more damage.

Gathering Storm

I take this rune over Scorch for the sole reason that Kassadin has a bad early game, and Scorch won't make him win lane either. I'd rather have the long scaling rune for the huge late game damages.

Presence of Mind

ATTENTION ATTENTION THIS IS THE BEST RUNE ON KASSADIN!!!! GIVES YOU MANA BACK WHEN YOU GET A KILL OR ASSIST. YOUR ULT BECOMES BASICALLY FREE SO YOU CAN JUST JUMP EVERYWHERE AND KILL EVERYONE

Coup de Grace

Great rune for any assassin that needs to finish off a kill with bonus execution damage.

Void Stone [Passive]

This useful ability is one of the reasons why Kassadin is a good anti-mage, reducing all magic damage by 15%. Also, it prevents that pesky minion block that nobody likes. Unfortunately, against AD champs, like Lucian, Zed, and Yasuo, Void Stone doesn't help you one bit.

Null Sphere [Q]

Against AP champions this ability is your bread and butter during laning phase. It does nice damage along with providing yourself with a magic shield every time you cast it. Coupled with Void Stone, you can avoid a large portion of enemy magic damage. Again, against AD matchups, Null Sphere takes lower priority to your E Force Pulse.

Nether Blade [W]

This ability has both a passive and an active. The passive gives you magic damage on-hit with all of your auto attacks, useful for farming and small trades. The active causes your next basic attack to be empowered and do bonus magic damage, along with restoring your mana. Nether Blade's active is an auto-attack reset, giving you deceptively high damage in the early game.

Force Pulse [E]

Force Pulse is a strange ability, being the only ability in the game that requires charges to even cast. Kassadin gains a charge whenever any ability is used in his vicinity. At 6 charges, he gains access to Force Pulse, which deals damage in the cone in front him, slowing all hit. This ability is great for catching someone out and for chasing. Also, against AD matchups it is the first ability you max.

Riftwalk [R]

This ability is Kassadin's real source of utility and mobility. Kassadin will teleport into the cursor, dealing damage to all hit. Each consecutive Riftwalk in a window of time costs double the mana and does bonus damage, stacking up to 4 times. Riftwalk's cooldown gets shorter as you level it up, until it is only a couple seconds long, meaning you have some of the most mobility in the entire game. Using Riftwalk, Kassadin can both escape most ganks, along with roaming to any lane pretty simply.

Dark Seal

Best starting item to pair with Refillable Potion. Gives a bit of mana, ap, and an opportunity to quickly snowball the game. Only buy Mejai's Soulstealer if you have the right amount of gold, and you feel like you can quickly take over the game.

Refillable Potion

Best item to pair along with Dark Seal. Give Kassadin some much needed sustain.

Rod Of Ages

This is your most important item. It gives you some nice health, mana, and AP, along with the nice Catalyst of Aeons passive.

Lich Bane

Take this is as your second item if you aren't behind. The Sheen proc along with your Nether Blade add to your full combo greatly.

Lucidity Boots

CDR is quite important on Kassadin. Pick these up for quicker ult cds, and to cover up for the lack of Insight .

Zhonya's Hourglass

A very simple Kassadin combo late into the game is to r+e into the enemy team, then proceed to Zhonya's Hourglass. This item is very important for survivability and the bit of armor, ap, and cdr.

Morellonomicon

This item is really nice for the long fights because of the mana regen items, althought it means you will have your powerspike a bit later. It's a good buy if you want to go into later game.

Void Staff

Liandry's Torment

Both of these are for teams that stack magic resist, or when an assassination target build a Maw of Malmortius or something like that.

Sorcerer's Shoes

Build this if you are ahead in lane by a good amount and have the right amount of money. This prevents your enemy laner from getting back into the game.

Iceborn Gauntlet

This might be the weirdest item to some, but it works like a charm. ONLY build this item if they have heavy AD damage, but still are squishy enough to oneshot.

Abyssal Mask

Similar to the Cassiopeia build with Abyssal Mask, this gives Kassadin tankiness and not bad damage, as it makes the opponent take more magic damage. Only build this against extremely strong AP.

Bansee's Veil

Good for a bit of AP, CDR, and magic resist, along with the useful spellshield against heavy cc

Mercury's Treads

Ninja Tabi

These are situational boots for if you are either geting cced for too long or if the other team has a lot of auto attack reliant champions.

Playing Kassadin in lane is the most important part of the game. Kassadin is a huge counter to most of the other AP champions as the true anti-mage. (Besides Galio) In lane, unless specified in the matchups list, you want to be spamming your Null Sphere on the enemy any time they come close to either cs or harass. A tip for playing Kassadin is to almost never use your Null Sphere on minions, as it is a huge waste of mana if your'e not getting harass on the enemy. This is different if you're against an AD champion, where you max E. You can Null Sphere minions for cs if you can't get close enough to auto attack.
For the first wave, you want to let the enemy push, as they are usually ranged champions. Make sure you hit level 2 before you let the minions hit your own turret. Nether Blade's passive and active allows you to farm quite efficiently underneath your own tower. Alternate between farming and harassing the enemy. If you bring Ignite you should play a bit more aggressively. Another tip is to always use your Nether Blade active whenever you can, as it restores your mana when it hits a target.
Final tip, while walking and roaming around, make sure to use your Nether Blade to stack up your Force Pulse charges. Riftwalk is Kassadin's bread and butter. When you hit 6 in lane, you gain a massive increase to your own kill pressure. Be sure to play much more aggressively in lane once you have your ult, using your full damage combo to land some huge poke.

Combo In Lane

Null Sphere into Force Pulse. Walk up and auto reset Nether Blade

Poking Combo

Null Sphere instantly into Force Pulse. Then you back off.

Full Damage Combo

Channel Nether Blade, then Null Sphere into instant Force Pulse into Riftwalk then empowered auto.