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.
If Master Yi tries to farm with Alpha Strike, hit him a few times so he has to use mana with Meditate to heal.
Although Master Yi cannot be slowed while using Highlander, other disables can stop him in his tracks.
Meditate is an effective method of healing damage over time, but Master Yi is susceptible to coordinated team ganks early in the game.
The stat comparisons shown on this page show several valuable Kassadin against Master Yi counter statistics that can help you appreciate the differences and similarities between the two. For instance, Kassadin’s KDA ratio ([kills + assists] / deaths) of NaN is more than Master Yi’s ratio of NaN, showing that Kassadin may be more central to his team's team fighting capacity than Master Yi..
Kassadin typically has a slightly smaller longest killing spree than his enemy does. On average, he receives a similar amount of damage to Master Yi. This typically indicates differing health capacities; however, it can also imply that the champion with higher health has less mobility and thus is unable to kite away from additional harm when engaged or poked.
Both League of Legends champions are great champions. Both champs have their strengths, weaknesses, and counters. In League's current meta, Kassadin usually loses when trying to fight Master Yi, with a 46.4% win rate. Therefore, Kassadin makes a poor counter for Master Yi.
While Kassadin does have a lower winrate compared to Master Yi, when they face off with one another, Kassadin also has a much greater learning curve that makes him a more complex champion to develop with. You may get destroyed when picking Kassadin into Master Yias his relative depth means you may not be able to unleash his full potential without a significant amount of practice beforehand.
Furthermore, Kassadin has some amount of CC and other utility, a similar amount to Master Yi. This often makes her just as valuable during team fights, especially when facing champions with a lot of burst damage.
While there is not a single best champion in League of Legends, in Kassadin vs Master Yi matchups, Master Yi is the better champ with a much lower win rate, more champion depth, and a similar amount of utility to help out your team members during teamfights.
Kassadin is a trash counter for Master Yi. Focus your actions on keeping up your gold and cs and taking out objectives. If you can do that, you should do very well as Kassadin against Master Yi.
If you would like to learn all of the intricacies of Kassadin in order to counter Master Yi during both the early game and mid / late game phases of League of Legends, you should continue reading to learn a few extra tricks and insights into this matchup. If you listen to the build and tips presented above, you should increase your win rate by a lot and be that much closer to League of Legends pro players.
Kassadin on average gets much more CS relative to Master Yi. Champions who typically don't get many minion kills typically don't need much CS to be valuable teammates, such as supports. These kinds of champions are able to scale well off of their skills, stats, and first items alone. Yet, champions with large amounts of CS, such as hyper-carries, often need a lot of items to be effective. In either case, try to surpass the numbers shown on this page to do well.
The best items to prioritize in your Kassadin versus Master Yi build include Malignance, Stormsurge, and Rod of Ages. When Kassadin combined at least these three pieces in his build, he performed significantly better versus Master Yi than with many other typical item sets. In fact, Kassadin had an average win rate of 46.4% battling Master Yi with this counter build.
To have the best likelihood of beating Master Yi 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. Out of all the rune sets players picked for Kassadin vs Master Yi matchups, this set of runes yielded the best win rate. Moreover, these runes gave a 46.4% winrate overall.
By default, tips, stats, and builds on how to beat Master Yi as Kassadin are displayed for all ranked divisions combined. If you would like to narrow the stats and builds to an individual rank, you should use the selection menu earlier in the counter matchup guide.