Fu Xuan is a Quantum-element character who follows the Path of Preservation. Her primary role is to mitigate damage received by her allies through her Skill and Talent.
Her Skill effect, Matrix of Prescience, redistributes the damage allies take to herself, with a fixed percentage of damage mitigation. At the same time, her entire team gains increased HP and CRIT Rate. Whenever Fu Xuan’s HP falls to 50% or below, her Talent’s second passive activates, restoring her HP. However, this requires at least one Trigger Count, which she gains from using her Ultimate, with a maximum of two stacks.
Best Cavern Relics
(2) Increases Max HP by 12%.
(4) When the wearer is hit or has their HP consumed by an ally or themselves, their CRIT Rate increases by 8% for 2 turn(s) and up to 2 stacks.
add(2) Reduces DMG taken by 8%.
(4) At the beginning of the turn, if the wearer's HP is equal to or less than 50%, restores HP equal to 8% of their Max HP and regenerates 5 Energy.
This is her best set so far for improving her DMG mitigation and reducing the damage she takes.
Best Planar Ornaments
(2) Increases the wearer's Effect RES by 10%. When the wearer's Effect RES is at 30% or higher, all allies' CRIT DMG increases by 10%.
This is her best Planar Ornament, as it provides a team-wide Crit DMG buff while also increasing her resistance to crowd control debuffs.
(2) Increases the wearer's Max HP by 12%. When the wearer's SPD reaches 120 or higher, all allies' ATK increases by 8%.
This is a good alternative for boosting her HP and providing a team-wide ATK increase.
Best Stats

Body
HP%

Boots
SPD

Sphere
HP%

Rope
Energy Regeneration Rate
Substats
HP% / SPD / Effect RES / DEF%
info
Fu Xuan primarily needs a large amount of HP, starting around 7000, and 1500 DEF to maintain longer damage mitigation uptime. Additionally, high Effect RES activates the Broken Keel buff and helps prevent control debuffs. A Speed stat of at least 135 is also recommended to ensure she takes turns more quickly.
Best Light Cones
SourceStellar Convergence, Light Cone Event Warp
Visioscape
Increases the wearer's Max HP by 24~40% and Energy Regeneration Rate by 12~20%. When the wearer's HP is reduced, all allies' DMG dealt increases by 9.0~15.0%, lasting for 2 turn(s).
At the start of every wave, restores HP to all allies by an amount equal to 80~100% of their respective lost HP.This Light Cone provides the best stat increases for durability and Ultimate uptime. It also boosts damage when her HP is reduced and restores HP to all allies at the start of every wave.
SourceStellar Warp, Light Cone Event Warp, Starlight Exchange, Stellar Convergence
Verdict
Increases the wearer's DEF by 24~40% and Effect Hit Rate by 24~40%. Increases the chance for the wearer to be attacked by enemies. When the wearer is attacked, increase their DEF by an extra 24~40% until the end of the wearer's turn.This greatly reduces the damage she takes through her damage mitigation; however, she doesn’t benefit from the Effect Hit Rate it provides since she doesn’t apply any debuffs.
Treasure
Increases the wearer's Effect RES by 8~16%. If the wearer is attacked and has no Shield, they gain a Shield equal to 16~32% of their Max HP for 2 turn(s). This effect can only be triggered once every 3 turn(s). If the wearer has a Shield when attacked, the DMG they receive decreases by 12~24%.This is her best free-to-play Light Cone, providing Effect RES and granting a shield whenever she takes damage. The shield further reduces the damage she receives.
SourceStellar Warp, Departure Warp, Character Event Warp, Light Cone Event Warp
A New Round of Shuffling
Increases the wearer's DEF by 16~32%. When the wearer is attacked, there is a 100~120% base chance to Burn the enemy. For each turn, the wearer deals DoT that is equal to 40~80% of the wearer's DEF for 2 turn(s).This Light Cone is effective for Acheron teams as it inflicts the Burn debuff whenever the wearer is targeted. Inflicting the Burn debuff grants one additional stack for Acheron’s Ultimate, allowing for faster Ultimate uptime.
SourceStellar Warp, Departure Warp, Character Event Warp, Light Cone Event Warp
Time Fleets Away
The wearer is more likely to be attacked, and DMG taken is reduced by 16~24%.This Light Cone increases her chance to be attacked while reducing the damage she takes.
SourceStellar Warp, Departure Warp, Character Event Warp, Light Cone Event Warp
At This Very Moment
Increases the wearer's DEF by 16~24%. After entering battle, increases All-Type RES of all allies by 8~12%. Abilities of the same type cannot stack.This enhances her durability and grants DMG RES to the entire team at the start of the battle.