Zeri has already proved she is a powerhouse in the bot lane, with enough movement speed to evade enemies and one of the best ultimates for extended team fights. When paired with a support like Lulu who can augment her damage and speed, they form an incredibly strong bot lane duo; let’s break down their synergy.
Zeri and Lulu Synergy: Laning Phase
Zeri and Lulu’s laning phase synergy is pretty safe thanks to their decent range, allowing them to farm minions and poke down the enemy from a safe distance. Considering the only form of hard CC is Lulu’s short-range Polymorph, it will be difficult to lock down and kill the enemy during the lane unless you are able to poke them down.
Generally, Lulu’s W (Whimsy) is better used defensively to nullify the enemy bot lane during trades or the enemy jungler during a gank to support their ADC. Zeri should use her Q (Burst Fire) for CS and to poke down the enemy, while her E (Spark Surge) can be used to trade aggressively or to escape when you’re vulnerable.
Considering Zeri's basic attack deals bonus damage to enemies below 35% health, it can be used to last hit minions. However, it should only be used to farm if you have missed killing the creep with your Q as it's much better to charge it up and use it to poke the enemy.
Zeri and Lulu Synergy: Team Fights
This duo’s synergy and true power lies in team fights. Zeri's passive (Living Battery) grants her 10% movement speed for 3 seconds whenever she receives a shield, which Lulu can easily provide with her E (Help, Pix!); this will shield Zeri, enhance her Q casts, and proc her passive to grant her movement speed.
Furthermore, Lulu’s W can be used offensively to support Zeri and grant her even more movement speed and attack speed, which also reduces the cooldown on her Q. It can also be used on an out of position enemy, as the polymorph will not only prevent them from using abilities to escape, but slows them and allows the Zeri to start damaging them. However, if an enemy is threatening your Zeri, the easy to land point-and-click CC can be used to buy time for your Zeri to escape or for your E to come back off cooldown.
Zeri’s goal in team fights is to get close to the enemies, land a multi-man ult to damage them and gain the bonus stats (movement speed, attack speed and extra damage), and continue to damage the enemy to maintain the bonuses.
Therefore, not only does Zeri gain all of these bonus stats from her ultimate, her damage and movement speed will be increased even more from Lulu’s W and E, providing strong synergy and support in teamfights.
Additionally, if Zeri is close to multiple enemies when she uses her ult, Lulu can use her ultimate to knock up those enemies, grant Zeri bonus health to help her survive, and slow enemies that are nearby to Zeri.
Zeri and Lulu Synergy: Build
Lulu can take Guardian or Summon Aery for her keystones as a support, as both provide another shield for Zeri and another way to proc her passive.
Guardian is the more defensive option and can be proceed even if Lulu isn’t in range as long as Pix is still attached to Zeri, while Summon Aery sacrifices some defence for extra poke damage.
Shurelya’s Battlesong is an excellent support item on Lulu as she can proc it with her W and E, and can provide even more movement speed for Zeri. Chemtech Putrifier should be picked up to shut down enemies with a lot of healing, while Ardent Censer, Staff of Flowing Water and Redemption as support items can increase your shields and buff your team even more. Watchful Wardstone can be purchasesd once Lulu has reached level 13, as it provides Lulu with the opportunity to place even more wards on the map and increases her ability haste and ability power exponentially.
As for Zeri, Trinity Force has emerged as an excellent Mythic. You will be spamming your Q throughout the game, and will be able to constantly proc the movement speed and bonus damage on your next basic attack. As your Q counts as a basic attack, its damage will be increased and amplified even further by picking up Titanic Hydra and Runaan's Hurricane. Wit's End is another great item for Zeri – particularly against AP threats – as its passive deals on-hit damage (which is procced by her Q) and increases Zeri's movement speed even more.
Lethal Tempo is the best keystone on Zeri as the attack speed reduces the cooldown of her Q and increases how much you can spam it. Additionally, Ingenious Hunter will reduce the cooldown of your Trinity Force.
Zeri and Lulu Synergy: Summary
Movement speed is the name of the game when it comes to this duo synergy, and if played correctly, they are unstoppable in team fights. Zeri players will need to keep an eye out for good ult opportunities, while the Lulu will have to react to Zeri’s speed and try to keep her alive.