Keeping tunnels spread out across the map will ensure you have choices when you want to cast Void Rush.
Cast Burrow before travelling around the map to take advantage of the increased Move Speed and the safety provided by Tremor Sense.
Tremor Sense can warn you of enemies closing in, and is particularly useful when entering enemy territory.
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.
The Rek'Sai Karthus synergy stats shown here demonstrate the areas of his gameplay that do better (or worse) when paired with Karthus, compared to his overall stats. Significant differences are areas of focus that highlight how his gameplay changes when paired with this other champion.
Overall, Rek'Sai sees a large worsening in his KDA (ratio of kills and assists to deaths) when paired with Karthus. His KDA worsened from NaN to NaN. This decrease shows that Karthus helps Rek'Sai perform not as well in ranked League of Legends rounds. Yet, the small difference demonstrates that this performance change is only marginal.
When Rek'Sai is an ally to Karthus, he sees a small decrease in his full damage output. This may demonstrate that Karthus does not support by providing cover for him to deal more damage or that his presence also helps extend the round's duration. Similarly, when Rek'Sai is played together with Karthus on the same team, he usually scores many fewer killing sprees than when he plays alone. This is contrasting evidence that he is worse when playing with Karthus.
Additionally, when Rek'Sai plays with Karthus on the same side, he often takes a little less damage than when he fights alone. Taking not as much damage could indicate that Karthus does a decent job of protecting Rek'Sai during teamfights.
There is no top ally for Rek'Sai that will always be his ideal synergy. However, overall, Karthus is a good companion for Rek'Sai. By playing on the same side as Rek'Sai, he raises their win rate by 2.5% to 50.9%. This clearly indicates that there is a somewhat important bond between Rek'Sai and Karthus that allows them to perform stronger together than alone.
Karthus has a much greater difficulty compared to Rek'Sai. That means Rek'Sai players need to be careful when finding Karthus comrades to go into battle on the same side as, as they will require a much greater level of skill to be able to cooperate well with you.
Fighting alongside, Rek'Sai players will likely observe an overall large increase in your team’s capacity to deal magical damage. Combined, these champs can blast through enemies with magic damage.
Although, by aligning Rek'Sai and Karthus together, you probably will not be giving your team a lot of tankyness. Make sure to bring other champs on your team that offsets this relative hole in this pairing's playstyle.
Regardless of the ability of your Karthus ally, you should focus on maximizing your income, staying alive by avoiding foolish fights, and clearing objectives. If you heed this simple advice, you should do well anyway.
If you would like to learn all of the intricacies of Rek'Sai in order to work well with Karthus during both the lane and mid / late game phases of League of Legends matches, you should continue reading to pick up a few extra tricks and insights into this champion pairing. If you pay attention to the build and stats presented above, you will increase your win rate by a lot.
The ideal items to use in your Rek'Sai and Karthus synergy build include Guardian Angel, Sterak's Gage, and Black Cleaver. When Rek'Sai combined at least these three pieces in his build, he performed a lot better when paired up with Karthus than with many other typical builds. In fact, Rek'Sai had an average win rate of 50.9% when playing alongside Karthus with this build.
To have the highest probability of annihilating your oponents, Rek'Sai players should take the Hail of Blades, Cheap Shot, Ghost Poro, Relentless Hunter, Celerity, and Gathering Storm runes from the Domination and Sorcery rune sets. Of all the runes players chose for this team composition, this blending of runes yielded the best win rate. Notably, these runes averaged a 50.9% winrate overall.
By default, tips, statistics, and builds on how to team up Karthus with Rek'Sai are given for all ranked divisions. If you would like to scope the stats and builds to a particular rank, you may use the selection menu located earlier on the page.