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.
Fizz's spells scale off Ability Power - consider getting items like Zhonya's Hourglass or Banshee's Veil against teams that have high burst threat - and items like Lich Bane or Rabadon's Deathcap if you think you can survive without the Health.
Since Fizz can move through units, find opportunities in lane to walk through minions and apply Seastone Trident's passive - following it up with the ability's active attack after a few seconds.
Fizz's ultimate ability, Chum the Waters, can be aimed at an enemy or towards the area where you think they'll be going.
The Kassadin Fizz synergy stats shown here demonstrate the areas of his gameplay that do better (or worse) when paired with Fizz, 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 Fizz. His KDA fell from NaN to NaN. This fall shows that Fizz helps Kassadin perform worse in ranked League matches. Yet, the small difference proves that this performance change is only marginal.
When Kassadin is an ally to Fizz, he sees a little decrease in his total damage dealt. This difference could signal that Fizz does not provide cover for him to dish out more damage or that his presence also helps extend the game's duration. Similarly, when Kassadin is played alongside Fizz on the same side, he usually scores many fewer killing sprees than when he plays without Fizz. This is contrasting evidence that he is worse when playing with Fizz.
Additionally, when Kassadin plays with Fizz on the same side, he often receives a little more damage than when he plays alone. Receiving more damage may mean that Fizz does a poor job of covering Kassadin during teamfights.
There is no universally accepted best ally for Kassadin that will no matter what be his #1 synergy. Yet, Fizz is a very bad companion for Kassadin. By playing on the same side as Kassadin, he drops their win rate by -3.6% to 46.4%. This shows that there is a very bad strategic relationship between Kassadin and Fizz that allows them to perform worse together than alone.
Fizz has a lower difficulty than Kassadin. That means you don't need to be cautious when enlisting Fizz teammates to play with, as they will have to have a relatively low level of skill to be able to play well with you.
When playing cooperatively, you should expect to see an overall large increase in your team’s ability to deal magic damage. When paired, these two can blast through enemies with magic damage.
Conversely, by pairing Kassadin and Fizz together, you probably will not be granting your team a lot of crowd control. Plan to pick other champs on your team that nullifies this hole in their abilities.
Regardless of your Fizz ally's ability, you need to focus on increasing your income, staying alive by avoiding foolish fights, and taking down objectives. If you heed this simple advice, you should do well anyway.
If you would like to truly master Kassadin to synergize with Fizz during both the early game and mid / late game phases of League of Legends matches, you should keep reading to learn a few extra tips and tricks for this champion pairing. If you pay attention to the build and stats displayed here, you will grow your win rate by a lot.
The most important finished items to prioritize in your Kassadin and Fizz synergy build include Seraph's Embrace, Lich Bane, and Malignance. When Kassadin used at least these three items in his build, he did a lot better as an ally of Fizz than with most other common item sets. In fact, Kassadin boasted an average winrate of 46.4% helping carry Fizz with these items in his kit.
To have the greatest probability of crushing your oponents, Kassadin players should use the Electrocute, Sudden Impact, Eyeball Collection, Ultimate Hunter, Presence of Mind, and Legend: Tenacity runes from the Domination and Precision rune sets. Out of all the rune combinations players chose for this team composition, this combination of runes resulted in the best win rate. Notably, these runes averaged a 46.4% winrate overall.
If you want to get Kassadin with Fizz synergy tips and builds for a a specific rank, feel free to choose one from the selection menu provided above. At first, the stats and guides given are computed using all rounds played with these champions.