Ein
Electric 
Sniper Rifle 
Attacker 
Burst 3 
Missilis Tier 2 Feather Standby
■ Activates when entering battle. Effects self.
Summons 4 Near Feathers.
■ Activates when entering Burst Skill Stage 3. Affects self.
ATK ▲ 70.12% for 10 sec.
Feather Shot
■ Activates when Near Feather is summoned. Effects 1 random enemy unit(s).
Near Feather Attack: Deals 90.81% of final ATK as true damage.
■ Activates when attacking with Full Charge. Affects self.
Charge Damage ▲ 80% for 1 shot(s).
Feather-All Range
■ Affects self.
Summons 6 Near Feathers.
True Damage ▲ 55.3% for 10 sec.
Charge Damage ▲ 140.68% for 10 sec.
■ Affects 10 enemy unit(s) with the highest DEF.
Deals 300.02% of final ATK as true damage.
Skill recommendations
Build
CUBES
If high level enough, you can use Rupture for the True DMG. If not, the usual suspects Resilience or Bastion are great for her.
OL GEAR
Elemental damage and ATK take priority. Since a lot of her damage comes from the drones, charge damage is not mandatory but always welcome. Max ammo capacity and crit as filler lines.
Solo Raid Usage
This is based on the top 50 players of all NIKKE servers combined. Data is from enikk.app, check their website for a lot more raid data.
Pros & Cons
- Simple to build damage dealer that's used in elemental content (mostly raids) and some campaign bosses like Mirror Container
- Can be used on most team compositions without any issues since her kit is pretty straightforward. You can also slot her with Miranda treasure to make the drones on burst constantly crit