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.
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 Kassadin 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, Kassadin sees a very large drop in his KDA (ratio of kills and assists to deaths) when paired with Karthus. His KDA decreased from NaN to NaN. This decrease shows that Karthus helps Kassadin perform not as well in competitive League of Legends games. Yet, the small difference proves that this performance change is only marginal.
When Kassadin is paired with Karthus, he sees a marginal improvement in his full damage dealt. This change could demonstrate that Karthus supports by providing cover for him to dish out more damage or that his participation also helps increase the game's duration. Similarly, when Kassadin is played alongside Karthus on the same side, he usually scores many fewer killing sprees than when he plays alone. This is contrasting evidence that he is worse when playing with Karthus.
Moreover, when Kassadin plays with Karthus on the same side, he often takes more damage than when he plays alone. Getting dealt more damage could indicate that Karthus does a poor job of covering Kassadin during teamfights.
There is no one best companion for Kassadin that will no matter what be his #1 teammate. Yet, overall, Karthus is a below average ally for Kassadin. By playing on the same side as Kassadin, he lowers their win rate by -2.5% to 47.5%. This shows that there is a bad bond between Kassadin and Karthus that results in them performing not as well together than without each other.
Karthus has a lower difficulty than Kassadin. That means Kassadin players don't need to be cautious when arranging Karthus teammates to fight alongside, as they will require a relatively low level of skill to be able to do well with you.
Fighting on the same side, Kassadin players should see an overall large increase in your team’s capacity to deal magical damage. Together, these two can deal quite a lot of AP type damage.
Conversely, by pairing Kassadin and Karthus together, you may not be giving your side very much anti-tank damage dealing potential. Make sure to include other champs on your team that fills this disparity in their kit.
Regardless of the skill of your Karthus ally, you should focus on increasing your gold income, warding to avoid ambushes, and clearing objectives. If you follow these simple suggestions, you will do well, regardless.
If you would like to truly master Kassadin to synergize with Karthus during both the lane and mid / late game phases of LoL games, you should keep reading to learn additional tips and tricks for this champion pairing. If you use the build and suggestions shown here, you should grow your win rate significantly.
The ideal items to build first in your Kassadin and Karthus synergy build include Seraph's Embrace, Rabadon's Deathcap, and Malignance. When Kassadin included at least these three pieces in his build, he did significantly better as an ally of Karthus than with many other typical builds. In fact, Kassadin had an average win rate of 47.5% when playing alongside Karthus with these items in his kit.
To have the best probability of defeating your oponents, Kassadin players should use 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 combinations we have analyed for this team composition, this combination of runes yielded the highest win rate. Notably, these runes gave a 47.5% win rate overall.
If you need to view Kassadin and Karthus cooperations tips and builds for a an individual skill level, feel free to select one from the selection menu above. If viewing for the first time, the statistics and guides shown are computed using every match with data with these champs.