Kassadin's ultimate has many uses and is on a shorter cooldown than most, use it often.
Kassadin has multiple item paths; he can go caster via Mana and Ability Power or anti-caster with Cooldown Reduction and Magic Resist.
Try to get the Ancient Golem buff to counteract Riftwalk's increasing Mana cost.
When Kayn is in terrain near you, you will get a visual warning on the edge of the terrain he's in.
Umbral Trespass requires Kayn to damage a target first. Try to dodge Blade's Reach to deny him a long range cast of Umbral Trespass.
Damage Kayn while he's in Shadow Step to shorten its duration, or apply hard crowd control (stun, charm, knockup, etc) to end Shadow Step immediately.
The stats provided here show several critical Kassadin versus Kayn counter statistics that may help you figure out the distinctions between this pair of champs. For instance, Kassadin’s KDA ratio ([kills + assists] / deaths) of NaN is greater than Kayn’s ratio of NaN, showing that Kassadin may be more central to his team's team fighting effectiveness than Kayn..
Kassadin often has a similar longest killing spree as his counter does. On average, he receives less damage than Kayn. This commonly reflects differing health capacities; however, it can also imply that the one champ has less agility and thus is unable to escape additional harm when poked or engaged.
Both League champions are great champions. Both champs have their pros and cons. In League's current meta, Kassadin usually wins when trying to fight Kayn, with a 51.6% win rate. As a result, Kassadin makes a good counter to Kayn.
While Kassadin does have a higher winrate compared to Kayn, when on opposite teams, Kassadin also has a greater learning curve that makes him a more difficult character to pick up and master. You should be careful when picking Kassadin into Kaynas his relative depth means that you may not be able to unleash his full potential without a lot of practice beforehand.
Furthermore, Kassadin also has some amount of CC and other utility, a similar amount to Kayn. This makes her just as valuable during team fights, especially when facing champions with a ton of burst damage.
While there isn't one best champion for every situation in League of Legends, in Kassadin vs Kayn matchups, Kassadin is the better champ with a higher win rate, similar champion depth, and a similar amount of utility to help out your team members during teamfights.
Kassadin is a decent counter for Kayn. You will do well by focussing your gameplay on increasing your CS and clearing objectives. If you can do that, you should do very well as Kassadin against Kayn.
If you would like to learn all of the intricacies of Kassadin to counter Kayn during both the laning and mid / late game phases of League of Legends, you should keep reading to gather a few extra tips and tricks for this matchup. If you mind the build and tips presented above, you will increase your win rate by a lot and be that much closer to League of Legends pro players.
Kassadin on average racks up much more CS relative to Kayn. Champions who typically don't take much CS often don't require much CS to be effective, such as sup champs. These kinds of champions are capable of scaling properly off of their abilities and first items alone. Yet, champs with large amounts of CS, such as hyper-carries, usually have to have many items to be effective. In either situation, try to do better than the numbers reported here to do well.
The most crucial items to focus on in your Kassadin versus Kayn build consist of Seraph's Embrace, Rabadon's Deathcap, and Malignance. When Kassadin bought at least these three items in his build, he performed much better when facing Kayn than with most other common item sets. In fact, Kassadin boasted an average winrate of 51.6% battling Kayn with these items in his kit.
To have the highest probability of defeating Kayn as Kassadin, you should equip the First Strike, Magical Footwear, Future's Market, Cosmic Insight, Sudden Impact, and Ultimate Hunter runes from the Inspiration and Domination rune sets. Of all the runes players used for Kassadin vs Kayn counterpicks, this mix of runes resulted in the highest win rate. Moreover, these runes gave a 51.6% win rate overall.
By default, tips, statistics, and builds on how to beat Kayn as Kassadin are presented for all ranked divisions combined. If you want to narrow the stats and builds to a specific rank, you can use the selection menu located earlier on the page.