If you have trouble landing Prismatic Barrier, remember that it returns to you after it reaches max range. Try positioning yourself to hit your allies with its return trip.
Lux has great zone control abilities. Try to set up Lucent Singularity to prevent an enemy's advance or escape.
Lucent Singularity is a great scouting tool. Try throwing it into brush before walking into it to check for ambushes.
Kai'Sa is very vulnerable to getting outranged by mages and long range carries.
Make sure to place wards in your blind spots so you can see Kai'Sa coming.
Kai'Sa is very good at picking off isolated enemies. Stick together against her.
The stat comparisons provided here emphasize several valuable Lux against Kai'Sa matchup statistics that can help you understand the distinctions between the two. For instance, Lux’s KDA ratio ([kills + assists] / deaths) of NaN is greater than Kai'Sa’s ratio of NaN, demonstrating that Lux may be more central to her team's team fighting effectiveness than Kai'Sa. This observation is in large part fueled by the differences in assists.
Lux often has a slightly smaller longest kill spree than her opponent does. Commonly, she receives less damage than Kai'Sa. This typically indicates different amounts of tankyness, but it can also show that the champion with increased health has less agility and thus is not able to escape additional damage when engaged or poked.
Both League champs are great. Both have their strengths, weaknesses, and counters. In the game's current meta, Lux usually wins when playing against Kai'Sa, with a 52.8% win rate. Thus, Lux makes a good counter to Kai'Sa.
While Lux does have a higher win rate compared to Kai'Sa, when facing one another, Lux also has a lower difficulty level that makes her a less difficult champion to learn and master. You should be be fine when picking Lux into Kai'Sa.
Moreover, Lux has a good amount of CC and other utility, a similar amount to Kai'Sa. This often makes her just as valuable during team fights, especially when facing champions with a ton of burst damage.
While there isn't a single best champion for every situation in League of Legends, in Lux vs Kai'Sa matchups, Lux is the better champ with a noticably higher win rate, less champion complexity, and a similar amount of utility to help out your allied champions during late stage team fights.
Lux is a good counter to Kai'Sa. Focus your strategy on increasing your gold and cs and destroying objectives. If you can do that, you should hold your own as Lux against Kai'Sa.
To truly master Lux in order to counter Kai'Sa during both the lane 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 pay attention to the build and stats displayed above, you should grow your win rate by a lot and be closer to League of Legends pro players.
Lux often gets less CS relative to Kai'Sa. Champs who on average don't earn many minion kills usualy don't require much CS to be effective, such as supports. They are capable of scaling properly off of their skills, stats, and first items alone. Yet, champs with large amounts of CS, such as hyper-carries, usually have to have several high cost items to be effective. In either situation, try to exceed the numbers reported on this page to do well.
The best items to have in your Lux versus Kai'Sa build consist of Rabadon's Deathcap, Malignance, and Stormsurge. When Lux incorporated at least these three pieces in her build, she performed significantly better when facing Kai'Sa than with many other common builds. In fact, Lux had an average winrate of 52.8% battling Kai'Sa with this build.
To have the highest probability of annihilating Kai'Sa as Lux, Lux players should take the First Strike, Magical Footwear, Biscuit Delivery, Cosmic Insight, Absolute Focus, and Gathering Storm runes from the Inspiration and Sorcery rune sets. Of all the runes players used for Lux vs Kai'Sa counters, this combination of runes resulted in the highest win rate. Notably, these runes gave a 52.8% winrate overall.
By default, tips, stats, and builds on how to beat Kai'Sa as Lux are displayed for all ranked divisions. If you want to scope the statistics and builds to a particular division, you should use the selection menu located earlier on the page.