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.
Despair is very effective against other tanks, so make sure you're in range of opponents with the highest Health.
Amumu is highly dependent on teammates, so try laning with your friends for maximum effectiveness.
Cooldown Reduction on Amumu is very strong, but it's often difficult to itemize for it. Grab the Golem buff whenever possible to gain Cooldown Reduction without sacrificing stats.
The Kassadin Amumu synergy stats shown here demonstrate the areas of his gameplay that do better (or worse) when paired with Amumu, 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 Amumu. His KDA decreased from NaN to NaN. This worsening shows that Amumu helps Kassadin perform not as well in ranked LoL matches. Yet, the small difference shows that this performance change is only marginal.
When Kassadin is an ally to Amumu, he observes a noticable increase in his complete damage dealt. This difference could demonstrate that Amumu helps provide protection for him to dish out more damage or that his presence on the team also helps extend the match's duration. Similarly, when Kassadin is played together with Amumu on the same side, he usually scores many fewer killing sprees compared to when he plays alone. This is contrasting evidence that he is worse when playing alongside Amumu.
Moreover, when Kassadin plays with Amumu on the same team, he often takes a little more damage than when he plays alone. Taking more damage could mean that Amumu does a poor job of protecting Kassadin in team fights.
There is no perfect champion pairing for Kassadin that will 100% of the time be his best teammate. Yet, Amumu is a good teammate for Kassadin. By being on the same side as Kassadin, he improves their win rate by 1.3% to 51.3%. This shows that there is a potentially meaningful synergy between Kassadin and Amumu that results in them performing at the top of their game together than alone.
Amumu has a much lower diffuclty than Kassadin. That means you don't need to be very careful when finding Amumu teammates to go into battle on the same side as, as they will have to have a much lower level of skill to work well with you.
Playing together, you should observe an overall large increase in your team’s capacity to deal magical damage. Combined, these two are able to dish out a surprising amount of magic type damage.
Conversely, by pairing Kassadin and Amumu together, you may not be giving your other allies much sustained damage output. Plan to have other champions on your team that helps cover this relative hole in their abilities.
Regardless of the skill of your Amumu teammate, you should focus on increasing your gold income, outlasting your enemies, and clearing objectives. If you do this, you will do well anyway.
If you would like to truly master Kassadin to pair well with Amumu during both the early game and mid / late game phases of LoL games, you should keep reading to gather some more tips and tricks for this champion pairing. If you listen to the build and tips displayed above, you will increase your win rate by a lot.
The ideal items to have in your Kassadin and Amumu synergy build include Rabadon's Deathcap, Malignance, and Rod of Ages. When Kassadin included at least these three finished items in his build, he performed significantly better when paired up with Amumu than with most other common builds. In fact, Kassadin boasted an average winrate of 51.3% helping carry Amumu with these items in his kit.
To have the greatest chance 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 runes players chose for this champion pairing, this set of runes yielded the greatest win rate. Moreover, these runes averaged a 51.3% win rate overall.
By default, tips, statistics, and builds on how to pair Amumu with Kassadin are given for all ranked divisions. If you would like to scope the stats and builds to an individual rank, you can use the selection menu located earlier in the counter matchup guide.