Rosaria is a 4-star Cryo polearm character added to Genshin Impact in patch 1.4. A mysterious nun from Mondstadt's Church of Favonius, Rosaria is a highly versatile Cryo character who can be built as either a DPS or a support.
MiHoYo has confirmed that Rosaria is returning in patch 1.6 as a rate-up character on Kazuha's banner, so now is a great time to check out her best builds.
Rosaria Genshin Impact Build Guide
Physical DPS Rosaria
As a Cryo character, Rosaria can easily activate Superconduct to reduce enemies' DEF for a period of time, making her well suited for the Physical DPS role.
Most 5-star damage-oriented polearm weapons, such as Primordial Jade-Winged Spear or Staff of Homa, will no doubt be a good fit on any DPS character. For those of us without premium weapons, though, Physical DPS Rosaria has plenty of 4-star weapons to choose from.
Crescent Pike and Dragonspine Spear are both craftable weapons that offer Physical DMG bonus as a substat, which work great with Physical DPS Rosaria. Other weapons such as Blackcliff Pole, Lithic Spear, and Deathmatch have conditional passives that can work well when activated.
For a Physical DPS, the best artifact build is two pieces of the Pale Flame set and two pieces of the Bloodstained Chivalry set, which add up to a whopping 50% Physical DMG bonus. Pick ATK% on your Sands, Physical DMG on your Goblet, and Crit Rate or DMG on your Circlet.
Cryo DPS Rosaria
Rosaria can turn into a Cryo DPS if you pair her with Chongyun, who can infuse her normal attacks with Cryo. This makes her normal attacks and her Elemental Skill / Burst hit equally hard.
The weapons of choice for Cryo DPS Rosaria aren't too different from Physical DPS Rosaria, except the weapons offering Physical DMG bonus are no longer needed. Aside from the 5-star weapons, Blackcliff Pole and Deathmatch are your best bets. You can also try Dragon's Bane if you plan to activate lots of Melt reactions.
Blizzard Strayer is the go-to artifact set for any Cryo DPS. With Blizzard Strayer, you'll want ATK% on your Sands, Cryo DMG on your Goblet, and Crit DMG on your Circlet. Crit Rate is not needed, because of the hefty bonus you get from the artifact set.
Sub DPS / Support Rosaria
Rosaria as a Sub DPS / Support focuses on using her Burst to continuously apply Cryo to enemies, as well as buffing her teammates' Crit Rate with her Ascension 2 passive.
Her weapons of choice won't be too different from her Cryo DPS build, but Favonius Lance and Prototype Starglitter are now valid options due to the Energy Recharge stat they provide. By using her Elemental Burst often, Sub DPS Rosaria can keep triggering reactions and activating her Ascension 2 passive.
The best artifact set to use on Sub DPS Rosaria is Noblesse Oblige, which buffs her teammates even more. You can also try mixing two pieces of Noblesse Oblige with two pieces of Gladiator's Finale or Blizzard Strayer. Pick ATK% or Energy Recharge on your Sands, Cryo DMG on your Goblet, and Crit Rate or DMG on your Circlet.