Label

A Burst 1 Defender Nikke who greatly boosts early survival in PVP against Electric Code-focused lineups.
She has clearer value in PVP than in general PVE, and also provides team ATK support.

Label's core is keeping her [Delusion] shield up to make the most of Skill 2's passive effects. [Delusion] is applied at battle start, and even after the shield breaks, normal attacks or Burst use restore [Delusion]. While in [Delusion], she keeps Burst Gauge filling speed increase, Increased ATK, and Damage Taken reduction for Damage taken from Electric Code enemies. Using her Burst [Bursting Heart]B switches to [Shared Delusion], making the shield she placed invincible, and during that time all allies except herself receive Increased ATK based on caster's ATK.

Auto is enough by default.
In the Arena, manually timing her Burst to match enemy Electric DPS's early damage window improves stability.

Manual input required

Prioritize Harmony Cubes that help with Label's ATK support, and choose based on your cube levels and stats.

Fill remaining lines mainly with options that help sustain ATK.

Skill 2 has the highest investment efficiency. Her Burst's shield invincibility duration is already fixed, so it is low priority.

Her PVP value is greatest for holding out against early damage from Electric Code enemies. In general PVE, she drops in priority outside specific matchups.

She greatly boosts early survival against Electric Code enemies and also provides ally ATK support when she uses her Burst.

Her strengths fade outside Electric-favored matchups, and her felt performance varies greatly by team composition.