Elegg: Boom and ShockLimited

A Water Burst 3 Machine Gun DPS Nikke.
She appears as a Water Code main DPS candidate in boss fights and Solo Raid.
You need to align her ghost capture cycle, overheat, and Burst timing together.

At battle start, one random enemy is Possessed, and every set number of normal-attack hits from all allies captures one ghost. This cycle repeats every few seconds, and ghosts stack up to the max. Water Code allies gain lasting Increased ATK based on caster's ATK and increased Elemental Advantage Attack Damage according to ghost count, and the more ghosts, the stronger both effects. Using her Burst Skill briefly grants herself Increased ATK, and if a ghost capture runs once more while ghosts are maxed, all enemies take another big hit. The Burst Skill itself attacks sequentially against random enemies, with the number of hits and ghosts consumed varying by ghost count.

Gather ally hits to ride the ghost capture cycle and raise ghost count.
While stacking ghosts up to 13, hold off on Burst Skill calls; once full, her Burst Skill attacks sequentially far more times.
When overheat fills, transition into a reload so hit accumulation isn't interrupted.

Reload and ammo keep Machine Gun hit accumulation steady. Pick the third cube to suit her gear. If Harmony Cube levels differ greatly, use the higher-level cube before the ranking.

Elemental Advantage Attack Damage and ATK are the baseline; add ammo to match the ghost buffs. Fill in crit with the remaining lines.

Ghost stacks and how many times the Burst attacks sequentially depend mostly on the first skill and Burst, so raise those first, then Ghostbuster2.

Fills the main DPS slot in stretches where you run multiple squads, such as Water Code boss fights and Solo Raid. Her Burst Skill attacks sequentially against random enemies, so with many mobs her damage is split across multiple enemies.

Grants Water Code allies lasting Increased ATK and increased Elemental Advantage Attack Damage based on ghost count.
With ghosts maxed out, the number of times her Burst Skill attacks sequentially rises sharply.
When a capture completes at max ghosts, all enemies take another big hit.

Her ghost capture and buffs need to match a Water Code lineup.
With few ghosts, her Burst Skill attacks sequentially fewer times.

Limited character.