Snow White: Innocent Days

An Iron Assault Rifle Burst 3 who makes her Burst window firepower huge with unlimited ammo and a high self Increased ATK.
Her area and all-enemy hits that cycle on 30-hit and 50-hit conditions help clear mobs and projectiles.
Relative to investment, there comes a point where she gives up the same slot to top meta main DPS units.

As normal attack hits accumulate, every 30 hits she stacks Increased Max Ammunition Capacity on herself, and at the same timing deals damage based on final ATK to enemies within attack range. Every 50 hits she deals damage based on final ATK to all enemies. Right after using her Burst Skill, she gains increased attack damage. Her Burst Skill Seven Dwarves IIIB grants herself Increased ATK and unlimited ammo and reduces the Seven Dwarves IV2 hit count condition by 20, so her second skill's all-enemy hit cycles more often within Full Burst.

Within 10 seconds after using her Burst Skill, keep normal attacks going without breaks to trigger conditions tightly.
The hit condition only counts bullets that deal damage.
Leave her on auto by default and only aim at weak points manually.

For Max Ammo, use the Wingman Cube to stabilize her rapid-fire conditions, and cover reload with the Resilience Cube. If you need more Burst Gauge, look at the Quantum Cube. If Harmony Cube levels differ a lot, use the higher-level cube before the ranking.

Keep Elemental Advantage damage and ATK lines. Hit Rate widens your margin for aiming at weak points. Her self Increased ATK is thick, so fill crit lines before Max Ammo lines.

Her Burst self Increased ATK and the attack damage increase from Seven Dwarves IV2 are the pillars of her firepower, so raise the Burst and S2 first. The S1 ammo stacks and extra hits can be filled relatively later.

In story, bosses, and Interception, she is valued both for clearing projectiles with frequent all-enemy hits and as a main DPS. In Arena she falls behind in raw firepower and Burst Gauge, so her priority is low.

Her Burst grants unlimited ammo, making it easy to cycle her hit-condition skills without breaks within the same Full Burst.
She frequently hits all enemies and areas, so she needs less hands-on effort against bosses with many destructible projectiles.

Her strong buffs only apply to herself, so she offers almost no squad-wide firepower support.
Once gear and skill investment pile up, she can fall behind top meta DPS units at the single-boss ceiling.