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.
A fully charged Vault Breaker will deal double damage. It's great for catching and finishing off fleeing enemies.
Relentless Force does full damage to anyone caught in the shockwave. Use it on minions in lane to hit enemies hiding behind them.
Cease and Desist is a powerful initiation tool, just remember not to get too far ahead of the rest of your team.
The Karthus Vi synergy stats shown here demonstrate the areas of his gameplay that do better (or worse) when paired with Vi, compared to his overall stats. Significant differences are areas of focus that highlight how his gameplay changes when paired with this other champion.
Overall, Karthus sees a large worsening in his KDA (ratio of kills and assists to deaths) when paired with Vi. His KDA worsened from NaN to NaN. This negative change shows that Vi helps Karthus perform poorer in ranked League of Legends rounds. Yet, the small difference demonstrates that this performance change is only marginal.
When Karthus is an ally to Vi, he sees a marginal improvement in his total damage dealt. This may indicate that Vi supports by providing protection for him to deal more damage or that her support also helps increase the match's duration. Similarly, when Karthus is played together with Vi on the same side, he usually scores many fewer killing sprees than when he plays on his own. This is contrasting evidence that he is worse when playing synergisticly with Vi.
Additionally, when Karthus plays with Vi on the same side, he typically receives much less damage than when he fights alone. Taking not as much damage could mean that Vi does a decent job of covering Karthus during team fights.
There is no universally accepted best ally for Karthus that will 100% of the time be his ideal ally. However, Vi is a superb companion for Karthus. By playing on the same team as Karthus, she raises their win rate by 3.8% to 51.1%. This proves that there is a very real synergy between Karthus and Vi that allows them to perform better together than alone.
Vi has a much lower diffuclty than Karthus. That means Karthus players don't need to be careful when lining up Vi comrades to fight alongside, as they will require a much lower level of skill to be able to do well with you.
Working alongside, you should observe an overall large increase in your team’s capability to deal magical damage. Together, these champions can deal quite a lot of AP type damage.
Although, by pairing Karthus and Vi together, you probably will not be granting your other allies a lot of protection for burst damage. Make sure to have other champions on your team that neutralizes this relative hole in this pairing's kit.
Regardless of the skill of your Vi teammate, you need to focus on maximizing your income, warding to avoid ambushes, and clearing objectives. If you do this, you will do well, regardless.
If you would like to learn all of the intricacies of Karthus in order to work well with Vi during both the early game and mid / late game phases of League, you should continue reading to learn additional lessons on this champion pairing. If you use the build and stats displayed here, you will grow your win rate significantly.
The most important finished items to use in your Karthus and Vi synergy build include Rabadon's Deathcap, Malignance, and Shadowflame. When Karthus combined at least these three pieces in his build, he performed significantly better when fighting alongside Vi than with most other common builds. In fact, Karthus had an average win rate of 51.1% when playing alongside Vi with these items in his kit.
To have the best likelihood of vanquishing your oponents, Karthus players should equip the Dark Harvest, Cheap Shot, Eyeball Collection, Ultimate Hunter, Presence of Mind, and Last Stand runes from the Domination and Precision rune sets. Of all the rune combinations players chose for this team composition, this composite of runes yielded the highest win rate. Moreover, these runes gave a 51.1% winrate overall.
By default, tips, stats, and builds on how to team up Vi with Karthus are presented for all skill levels, merged. If you would like to scope the statistics and builds to a specific player tier, you should use the selection menu earlier in the counter matchup guide.