Be a bird!
In the lane, try to position your soldiers between the enemy's minions and the enemy champion. This way you can use them both to last hit and to project threat onto your lane opponent.
Be careful about putting down both of the soldiers stored by Arise! Unless you're going all-in, always have a soldier in your back pocket if you need to escape over a wall or if you misposition your other soldier and need damage now.
Think of Emperor's Divide as a defensive ability first and foremost. Use it when the enemy engages on you or your allies. Remember that your team can walk through the soldiers summoned by Emperor's Divide and use this to your advantage when enemy melee champions engage on you.
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 Azir 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, Azir sees a very large drop in his KDA (ratio of kills and assists to deaths) when paired with Karthus. His KDA went down from NaN to NaN. This fall shows that Karthus helps Azir perform poorer in ranked League rounds. Yet, the small difference indicates that this performance change is only marginal.
When Azir tries to synergize with Karthus, he gets a barely noticable drop in his complete damage output. This change could indicate that Karthus does not provide protection for him to deal more damage or that his allyship also helps extend the match's duration. Similarly, when Azir 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.
Additionally, when Azir plays with Karthus on the same team, he often takes a little more damage than when he plays alone. Taking more damage could mean that Karthus does a poor job of covering Azir in teamfights.
There is no perfect synergy for Azir that will no matter what be his #1 synergy. Yet, overall, Karthus is a very bad ally for Azir. By locking into the same team as Azir, he decreases their win rate by -8.6% to 41.6%. This clearly indicates that there is an easy to overcome and exploit bond between Azir and Karthus that allows them to perform not as well together than without each other.
Karthus has a lower difficulty than Azir. That means Azir players don't need to be very careful when enlisting Karthus comrades to fight alongside, as they will require a relatively low level of skill to do well with you.
Working on the same side, you will likely see an overall large increase in your team’s capability to deal magic damage. When paired, these champs are able to dish out a surprising amount of magic type damage.
In contrast, by pairing Azir and Karthus together, you probably will not be granting your side a lot of protection for burst damage. Plan to include other champs on your team that helps cover this hole in this pairing's abilities.
Regardless of your Karthus ally's ability, you need to focus on maximizing your gold income, warding to avoid ambushes, and clearing objectives. If you follow these simple suggestions, you should do well, regardless.
If you would like to truly master Azir in order to work well with Karthus during both the laning and mid / late game phases of LoL games, you should keep reading to pick up additional tips and tricks for this champion pairing. If you listen to the build and tips displayed here, you will grow your win rate significantly.
The best items to use in your Azir and Karthus synergy build include Rabadon's Deathcap, Nashor's Tooth, and Shadowflame. When Azir incorporated at least these three finished items in his build, he performed much better when paired up with Karthus than with many other commonly used builds. In fact, Azir boasted an average win rate of 41.6% when synergizing his build and playstyle to Karthus with these items in his kit.
To have the best likelihood of beating your oponents, you should take the Fleet Footwork, Presence of Mind, Legend: Alacrity, Coup de Grace, Manaflow Band, and Scorch runes from the Precision and Sorcery rune sets. Of all the rune sets players chose for this champion pairing, this composite of runes resulted in the top win rate. Notably, these runes provided a 41.6% winrate overall.
If you would like to get Azir and Karthus collaboration tips and stats for a a distinct skill level, feel free to select one from the selection menu provided above. By default, the stats and guides given are calculated using every round played with both champions.