Lay Waste is very strong at farming minions and harassing enemy champions.
Ask your allies to help point out when you should use Requiem to get kills in different lanes.
Zilean is fragile if a team focuses on him, but otherwise he's very difficult to kill. Commit to killing him as a team.
If you're able to match Zilean's speed, it can sometimes be beneficial to wait until his ultimate has faded before landing the killing blow.
The stats provided here emphasize several important Karthus vs. Zilean matchup statistics that can help us appreciate the distinctions between the pair. Karthus’s KDA ratio ([kills + assists] / deaths) of NaN is more than Zilean’s KDA ratio of NaN, demonstrating that Karthus may be more central to his team's team fighting capacity than Zilean. This observation is in large part fueled by the differences in killsdeaths.
Karthus usually has a much larger longest kill spree than his matchup does. Typically, he takes more damage than Zilean. This commonly reflects different amounts of tankyness, but it can also hint that the champion with increased HP has less agility and thus is not able to kite away from further harm when poked or engaged.
Both League of Legends champs are great champions. Both have their strengths, weaknesses, and counters. In League's current meta, Karthus usually fairs equally well when taking on Zilean, with a 49.2% win rate. Therefore, Karthus makes an ok counter to Zilean.
While Karthus does have a lower win rate than Zilean, when they face off with one another, Karthus also has a greater difficulty level that makes him a more time consuming character to develop with. You should be careful when picking Karthus into Zileanas his relative depth means that you may not be able to unleash his full potential without a lot of practice beforehand.
Moreover, Karthus also has some amount of CC and other utility, a similar amount to Zilean. This often makes her just as valuable during team fights, especially when facing champions with a ton of burst damage.
While there is not one best champion for every situation in League of Legends, in Karthus vs Zilean matchups, Zilean is the better champ with a similar win rate, more champion depth, and a similar amount of utility to help out your allied champions during late stage team fights.
Karthus is a somewhat poor counter for Zilean. Make sure you focus your actions on maximizing your gold income and clearing objectives. If you do that, you should do very well as Karthus against Zilean.
To truly master Karthus to counter Zilean during both the lane and mid / late game phases of League of Legends, you should continue reading to pick up a few extra tips and tricks for this matchup. If you listen to the build and tips shown here, you will grow your win rate by a lot and be closer to League of Legends pro players.
Karthus most often gets more CS relative to Zilean. Champs who typically don't acquire many minion kills typically don't require much CS to be effective, such as sup champs. These kinds of champions are able to scale well off of their abilities and first items alone. Yet, champs with a lot of CS, such as hyper-carries, usually need many items to be effective. In either case, try to do better than the values reported here to do well.
The most crucial items to focus on in your Karthus versus Zilean build include Malignance, Stormsurge, and Liandry's Torment. When Karthus included at least these three pieces in his build, he did significantly better when facing Zilean than with most other typical counter builds. In fact, Karthus boasted an average win rate of 49.2% battling Zilean with this counter build.
To have the greatest probability of beating Zilean as Karthus, you should use the First Strike, Magical Footwear, Future's Market, Cosmic Insight, Eyeball Collection, and Ultimate Hunter runes from the Inspiration and Domination rune sets. Out of all the rune combinations players chose for Karthus vs Zilean battles, this mixture of runes resulted in the highest win rate. Notably, these runes gave a 49.2% win rate overall.
By default, tips, statistics, and builds on how to beat Zilean as Karthus are displayed for all ranked divisions combined. To narrow the statistics and builds to a specific rank, you may use the selection menu located earlier on the page.