Fu Xuan is a Preservation character in Honkai: Star Rail whose ability scales with HP instead of DEF. With her Skill, she places a Matrix of Prescience, which reduces the DMG taken by the entire team while also boosting her allies’ HP and Crit Rate. The Crit Rate bonus only scales with her Skill level, but the HP buff scales with the Master Diviner’s max HP, which means it’s best to stack on health when playing her.