This Build focuses on Rosaria's Buffing/Energy generation/Cryo application capabilities. Though it does not mean that you dont invest in her personal damage, only that it's a lower priority overall.
Rosaria A4 passive provides a potent CRIT Rate buff to her teammates via her own CRIT Rate after casting Burst. This heavily incentivizes building enough Energy Recharge to Burst consistently and getting as close to 100% CRIT Rate as possible
Regarding Weapon Choices:
Favonius Lance: The best option in situations where you havent met your teams Energy Recharge requirements. Outside of that scenario you would be better off using a CRIT Rate weapon that benefits her A4 buff.
Regarding Artifact Choices:
Sets
Scroll of the Hero of Cinder City (4): Unconditional 12 DMG% to any element that she reacts with, (2) also help her Energy Recharge requirement when there is a Nightsoul Burst triggered in the party
Archaic Petra (4): Only used in teams where she can reliably pick up Crystalized crystals
Instructor (4): Can be the better option in teams that prefer the Elemental Mastery buff over ATK, such as Hu Tao VapeMelt, while sacrificing her CRIT Rate buffing potential
Substats
Energy Recharge: Prioritize until requirements are met.
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Indicates important notes at the bottom of the page.
This build can be used on both a quickswap/sub-dps and perma-Freeze dps Rosaria. Generally played as a secondary DPS to an onfield Freeze carry like Kamisato Ayaka, Ganyu, Wriothesley.
If Rosaria is being used with Chongyun to infuse her Normal Attacks with Cryo, her Normal Attack talent will have higher priority than Skill.
Regarding Weapon Choices:
120% Energy Recharge requirement, some weapons requires 0 rolls into CRIT Rate
Calamity Queller: Assumed max stacks, passive not doubled
Vortex Vanquisher: Assumed 2 stacks, unshielded.
Primordial Jade Winged-Spear: Assumed 2 stacks.
Wavebreaker's Fin: At high refinement [R4-R5] with a 270 energy cost team, this weapon perform just below .
Regarding Artifact Choices:
Sets
Emblem of Severed Fate (4): CRIT Rate secondary stat weapon only.
Noblesse Oblige (4): This set is only used in her quickswap/support roles not her perma-Freeze dps role. Also it should only be considered when you have no decent (4) pieces and no one else on the team is holding (4).
Substats
Energy Recharge: Prioritize until requirements are met.
CRIT Rate: Some weapons requires 0 rolls into CRIT Rate.
ⓘ
Indicates important notes at the bottom of the page.
This build capitalizes on the fact Rosaria's Skill and Burst don't have an ICD, allowing her to Melt all Skill and Burst procs. Which in combination with snapshotting buffs onto her Burst makes it one of her highest personal damage builds.
Be sure to cast Skill before Burst as CRIT Rate granted by the Ascension 1 Talent will be included with Ascension 4 Talent Bonus as well.
Rosaria's Skill and Burst can be Reverse Melted (1.5x) with another Pyro applier for some quick and powerful damage.
Calamity Queller: Ranking assumes fully stacked passive, and the passive is not doubled.
Vortex Vanquisher: Ranking assumed shielded, if unshielded, this weapon performs slightly better than [R1].
Deathmatch: At high refinement [R4-R5] with 2+ enemy, this performs just below . This weapon can outperform all 4-star options and even when used with (4) in single target situations.
Dragon's Bane: At high refinement [R4-R5] this weapon performs slightly better than .
Wavebreaker's Fin: At high refinement [R4-R5], this weapon performs just below .
Regarding Artifact Choices:
Sets
Emblem of Severed Fate (4): In teams where her Energy Recharge requirements are higher (130%+) it can surpass (4).
Substats
Energy Recharge: Prioritize until requirements are met.