The goal of this build is to prioritize Layla's shield without building for personal damage.
Regarding Weapon Choices:
Primordial Jade Cutter: This weapon sees more value on Layla when you're also investing into her damage to some extent.
Favonius Sword: Try to build some CRIT Rate if using this weapon to trigger the passive consistently.
Freedom-Sworn: This weapon can be a good support option in teams where Layla can consistently trigger the passive.
Regarding Artifact Choices:
Sets
Tenacity of the Millelith (4): This set is by far the best option for Layla, it complements her kit perfectly by providing HP% along with a teamwide ATK% and Shield Strength buff.
Main Stats
CRIT Rate: Only recommended if using a Favonius weapon.
Substats
Energy Recharge: Prioritize until requirements are met.
CRIT Rate: Only recommended if using a Favonius weapon.
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Indicates important notes at the bottom of the page.
Layla's shield is very durable thanks to a good Base DMG Absorption and the number of Shield Strength modifiers she has access to. Furthermore, her personal damage scales well with Constellations (particularly 5 and 6). This build is a higher investment option than a pure Support build, choosing to sacrifice some shield durability in exchange for greater personal damage.
Regarding Weapon Choices:
Harbinger of Dawn: Weapon ranking is assuming Layla is above 90% HP. As Layla is primarily used as an off-field character, she can usually have good uptime on the passive. Though it's possible that good uptime may be unrealistic depending on your team, or if you're facing enemies where corrosion is present.
Wolf-Fang: At [R5] this weapon performs similarly to [R5].
Favonius Sword: This weapon performs significantly worse than other listed options in terms of personal damage, but the extra particles for your team could be valuable.
Regarding Artifact Choices:
While a HP%/Cryo DMG/CRIT build is ideal for personal damage, additional HP% Main Stats can be used to increase shield durability without a huge drop in personal damage as Layla's damage is partially Flat HP scaling.
Sets
Tenacity of the Millelith (4): This set is by far the best option for Layla's shield durability, and very often the best set for team damage.
Blizzard Strayer (4): This is Layla's best set for personal damage in teams where enemies are affected by Cryo or Frozen.
Main Stats
Energy Recharge: Layla's Energy Recharge requirements will generally be low enough (especially with C2 or other Cryo characters) that an Energy Recharge sands is not justified.
Substats
Energy Recharge: Prioritize until requirements are met.