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.
Janna's at her strongest when buffing another ally. If you can harass her ally, it will weaken her ability to fight you.
Save an interrupt ability for when Janna uses her ultimate.
Listen for the charge up sound on Howling Gale in case Janna is trying to hit you with it from off screen or from brush.
The stats shown here clarify some influential Kassadin vs. Janna matchup statistics that may help us explain the distinctions between the two. Kassadin’s KDA ratio ([kills + assists] / deaths) of NaN is greater than Janna’s ratio of NaN, demonstrating that Kassadin may be more central to his team's team fighting potential than Janna. This observation is in large part fueled by the difference in kills.
Kassadin often has a much larger longest kill spree than his matchup does. Commonly, he receives more damage than Janna. This commonly reflects different amounts of tankyness, yet it can also show that the champion with more HP has less mobility and thus is not able to escape further damage when poked or engaged.
Both LoL champions are great. Both champs have their pros and cons. In League's current meta, Kassadin usually fairs equally well when taking on Janna, with a 49.2% win rate. As a result, Kassadin makes an ok counter to Janna.
While Kassadin does have a lower win rate than Janna, when facing one another, Kassadin also has a greater difficulty level that makes him a more challenging champion to develop with. You should be careful when picking Kassadin into Jannaas his relative depth means you may not be able to unleash his full potential without a lot of practice beforehand.
Additionally, Kassadin has some amount of utility and CC, a similar amount to Janna. This makes her just as valuable during teamfights, especially when trying to counter champions with a ton of burst damage.
While there is not one best champion overall in League of Legends, in Kassadin vs Janna matchups, Janna is the better champion with a similar win rate, more champion depth, and a similar amount of utility to help out your teammates during late stage team fights.
Kassadin is a somewhat poor counter for Janna. Make sure you focus your gameplay on maximizing your gold income and destroying objectives. If you do that, you should be able to stand on your own as Kassadin against Janna.
If you would like to truly master Kassadin to counter Janna during both the laning and mid / late game phases of League of Legends, you should continue reading to pick up a few extra lessons on this matchup. If you pay attention to the build and tips presented above, you will increase your win rate significantly and be that much closer to League of Legends pro players.
Kassadin most often racks up much more CS as Janna. Champs who on average don't acquire many minion kills often don't require much CS to be valuable teammates, such as support champions. They are able to scale properly off of their abilities and first items alone. Yet, champs with a lot of CS, such as hyper-carries, often need several high cost items to be effective. In either case, try to surpass the values reported on this page to do well.
The best items to focus on in your Kassadin versus Janna build include Rabadon's Deathcap, Malignance, and Rod of Ages. When Kassadin incorporated at least these three pieces in his build, he performed a lot better against Janna than with many other typical item sets. In fact, Kassadin boasted an average win rate of 49.2% battling Janna with this counter build.
To have the highest probability of vanquishing Janna as Kassadin, you should take 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 picked for Kassadin vs Janna counterpicks, this combination of runes yielded the greatest win rate. Moreover, these runes gave a 49.2% winrate overall.
By default, tips, statistics, and builds on how to beat Janna as Kassadin are given for all ranked divisions combined. If you want to filter the stats and builds to a distinct division, you may use the selection menu earlier on the page.