Auto-attack to apply a Plasma stack, Q for the missiles (which deal more damage to isolated targets), then auto-attack again.
Kai'Sa Wild Rift Expert Guide
§ 07b — Advanced MechanicsKai'Sa: combos & tips Wild Rift
Supercharge for invisibility + attack speed, auto-attack, Q burst, finish with E.
E marks the target, R dash onto them with shield, full burst with Q and auto-attacks.
Q for the missiles, rapid auto-attacks with W attack speed, R for the execute.
FAQ
How should I play Kai'Sa in Wild Rift?
Kai'Sa is generally played as ADC. The first objective is to priority farm; trade short to post-e initiative. Its biggest edge comes from good follow-up thanks to r + shield.
When is Kai'Sa strongest?
Kai'Sa takes over in mid game: 2 items: looking for skirmishes 3v3/4v4.
How do I punish Kai'Sa?
Kai'Sa can be punished when no real escape outside r/e (careful to channel). A practical answer listed here is: Block his W angles with the minions and play behind your controls.