He is an adeptus, under the name Alatus, and the only known remaining member of the five foremost Yakshas dispatched by Morax to subdue the demonic spirits that plagued Liyue. He currently resides in Wangshu Inn and mostly secludes himself from crowds and human interactions.
No elemental particles are generated while the Elemental Burst Bane of All Evil is active.
When obtaining Xiao's Constellation 1, Dissolution Eon: Destroyer of Worlds, wind cycling gains 1 extra charge bringing the total to 3 charges.
When obtaining Xiao's Constellation 6, Conqueror of Evil: Guardian Yaksha, Xiao gains access to "infinite cycling." That is, while in his yaksha phase Bane of All Evil, as long as Xiao continuously hits at least two opponents with his plunge attack, he will continuously gain extra wind cycling charges that he can use free of cooldown.
The skill is very useful for exploration. It can be used to traverse horizontal gaps and cover greater horizontal distances without consuming extra sprinting stamina (effectively acting like a sprinting boost).
The skill can be used while gliding to cover further horizontal distance. If used correctly, Xiao can stay airborne and recover some stamina, which is helpful for reaching places like the Nameless Island. It can also be used to close gaps in combat and quickly evade certain enemy attacks.
When Xiao is affected by an element such as Pyro, Hydro, Electro, Cryo, wind cycling can be used to spread the applied elemental status within an area via the Swirl reaction. This is useful within combat to trigger reactions or for even lighting up Elemental Monuments.
Since it can be used midair, a common trick is to jump, then use wind cycling (2-3 times) to hit enemies, and then plunge attack.
For example, when using Venti's Wind's Grand Ode, Xiao can hit the enemies in the vortex by jumping and using the wind cycling attack.
Converts attack DMG into Anemo DMG, which cannot be overridden by any other elemental infusion.
In this state, Xiao will continuously lose HP. The effects of this skill end when Xiao leaves the field.
With Xiao's 6th Constellation, Conqueror of Evil: Guardian Yaksha, and using Bane of All Evil, Xiao gains 1 additional charge of Lemniscatic Wind Cycling every time two enemies are hit with his Plunging Attack. For the next 1s, he may use Lemniscatic Wind Cycling while ignoring its cooldown. This allows him to perform "infinite-cycling" during this 1s period.
Xiao can release ~10 plunge attacks over the skill duration.
A common attack sequence (especially for Bosses or other single target enemies) is to jump, plunge attack, perform a Normal Attack / Charged Attack, and repeat, canceling the Charged Attack into another jump. This is to deal more damage than just jumping and plunging without adding the extra Normal Attacks in between. This attack sequence is sometimes referred to by players as "N1CJP" (Normal 1, Charged, Jump, Plunge).
Because Xiao jumps higher than the threshold for a high plunge, Xiao can plunge sooner, before reaching the peak of his jump, delivering 12 plunge attacks instead of 10 while maintaining High Plunge Damage and minimizing air time. (A good reference for such altitude is just above Zhongli's Stone Stele.) Also, by pressing Normal Attack right before Xiao lands, Xiao can immediately jump again without releasing an actual Normal Attack. This reduces the time lag between plunge attacks. A good place for practicing this version is in the Spiral Abyss, where Xiao will always have Elemental Burst ready.
Xiao's plunge attacks will increase AoE damage, producing multiple spears from the ground around where he lands as a visual enhancement. His plunge attacks can stun-lock large enemies, including Lawachurls and Geovishaps and break the rock and ice shields on Hilichurls and Mitachurls, as well as break the elemental shields on Abyss Mages.
Sometimes to dodge attacks, it is helpful to stay in the air longer by gliding a bit before plunging down.
It may be helpful to bring a healer, especially for the floors on the Spiral Abyss, to counteract the HP drain from Bane of All Evil. Outside of the Spiral Abyss and in areas where food is allowed, one can use an NRE (Menu 30) pouch to provide quick healing to Xiao while he is on the field.
Besides attacking enemies in battle, Bane of All Evil can also be used for exploration. Because of the increased jumping ability it provides, Xiao can use it to scale mountain cliffs and reach high, hard-to-reach places just by jumping.
The jump boost can also be used to bypass tall obstacles and evade certain enemy attacks by jumping over them, such as the Anemo Hypostasis' Anemo wave or the Electro Hypostasis' spinning electric rays.
Xiao can sometimes jump high enough to hit many flying enemies in the game, such as the Ruin Hunter.
Currently, Bane of All Evil is the only ability in the game that increases the character's jump height, giving Xiao the highest vertical mobility.
In this state, Xiao's Elemental Skill, Lemniscatic Wind Cycling, will not generate elemental particles, though all other sources still generate energy normally.
Because of this, it is usually optimal to use Xiao's wind cycling charges before immediately activating his Elemental Burst so that he can fund the energy particles generated from the wind cycling towards the 2nd Elemental Burst.
Usually, it is desirable to have a so-called "energy battery" on Xiao's team to maintain Elemental Burst's uptime. An "energy battery" for Xiao is an Anemo-based character that can provide lots of Anemo particles to recharge Xiao's energy. Sucrose, Jean, and Venti are viable choices, with Jean able to play the role of both healer and battery.