Liter

One of the most used Burst 1 buffers in Solo Raid and long boss fights.
Liter Boost1's stacking cooldown reduction, Double BoostB's ATK, and Volt Boost2's cover recovery are her core.
Her effects stack with the number of Full Bursts and Burst Skill uses, so the first 3 rotations lose a lot.

Each time Full Burst starts, Liter Boost1 reduces all allies' Burst Skill Cooldown in stages, and each time an ally uses a Burst Skill she applies Max Ammo, Critical Damage, and ATK buffs in order. Double BoostB greatly raises all allies' ATK.

Volt Boost2 restores the cover of the 2 allies with the lowest cover HP. She is a Burst 1 support with a 15-sec skill cooldown and a 20-sec Burst cooldown.

Keep the Burst order going so Full Burst isn't interrupted.
Leave firing and Burst on Auto.
When using her with Grave in Solo Raid, only adjust lineup timing so the gap from one Full Burst to the next stays short.

Build long-fight survival with HP and damage taken reduction. If you already have another high-level Harmony Cube, look at level before ranking.

Skip DPS-oriented Elemental Advantage and ATK lines. If you're padding CP, consider Max Ammo, Hit Rate, DEF, and Burst Gauge lines.

Raise Liter Boost1 and Double BoostB first, and keep Volt Boost2 low. Stacking cooldown reduction and the ATK buff are her core.

Often slotted in Story, bosses, and Solo Raid for Burst 1 buffs and cooldown reduction. In early Story stretches dominated by mobs, she loses a lot before her stacks build, so she fits less well.

Every Full Burst, she reduces Burst Skill Cooldown in stacks.
Each time a Burst Skill is used, she applies Max Ammo, crit, and ATK buffs in stages.
Double BoostB greatly raises allies' ATK.
Volt Boost2 restores cover HP, which can free up a healer slot.

Her stacking cooldown reduction only reaches its maximum after Full Burst and Burst Skill each stack 3 times, so early rotations lose a lot.
Her personal damage and Burst Gauge contribution are low.
Her role overlaps with instant cooldown reducers like Little Mermaid and Red Hood, as well as Volume and Helm.

Paired with ammo-refund Nikkes, Liter Boost1's Max Ammo support becomes more valuable. Without Grave, it's hard to reach peak stacking cooldown reduction.