HelmHas Favorite Item

A Water Sniper Rifle Nikke who, at Burst 3 with her Favorite Item, can apply single-target damage, ally healing, and a Charge Damage multiplier together.
Meeting Full Charge and last-bullet conditions lets her cycle Critical Rate, Burst Gauge, and healing all at once.
Her Burst scaling and Charge bonuses are large, so with proper investment she deals solid damage herself.

All allies always have increased Damage to Interruption Parts.
Landing the last bullet raises allies' Critical Rate, and landing a Full Charge heals allies and fills their Burst Gauge.
When Full Burst starts, allies get additional increased attack damage.
Each Full Charge hit adds extra damage to the enemy hit.
Her Burst Skill deals single-target damage to the enemy with the highest ATK, heals all allies, and briefly raises her own Charge Damage multiplier to boost her shot damage at that moment.

Use Full Charge shots to apply healing and Burst Gauge.
Land the last bullet of the magazine on an enemy to apply Frontline Command's normal attack Critical Rate buff to all allies.
During Full Burst, Aegis Cannon's Charge Damage multiplier and Fire Away's Full Charge extra damage stack, so landing Full Charge shots is better for damage than the last-bullet buff. The Frontline Command crit buff can be reliably triggered after Full Burst by emptying the magazine and landing the last shot on an enemy just before reloading.
Auto alone works, but mixing in manual aim is safer for the above conditions. Lower ammo shortens the last-bullet cycle, so you can apply the same buff more often.

Cut reload tempo with Resilience Cube. Support ammo recovery with Bastion Cube. If Full Charge matters a lot, Adjutant Cube for Charge Speed is the next option. If Harmony Cube levels differ a lot, use the higher-level cube before following the ranking.

Set Elemental Advantage damage and ATK first. Use Charge Speed and Charge Damage to reinforce her Burst and Fire Away extra damage windows.

Aegis Cannon's scaling and Charge Damage multiplier are large, so raise Burst first. Fire Away holds Full Burst attack damage and Full Charge extra damage, so raise S2 next. Frontline Command holds Critical Rate and Full Charge-linked healing and gauge, so fit S1 after that.

Can be fielded in story, bosses, and Tower when aiming for single-target damage, healing, and attack damage buffs together. Her priority drops in Arena.

Her Full Charge heals allies and fills Burst Gauge.
Full Burst and her Burst Skill can stack ally attack damage buffs and healing.
Her Burst raises her Charge Damage multiplier, boosting her own damage too.

Missing last-bullet and Full Charge timing lowers combo efficiency.
Her Burst 3 slot easily overlaps with other DPS Nikkes, so she is sometimes left out depending on content and team.