Belka
SSR Assault Rifle Electric VanguardCharacter notes
The 2nd (3rd without dupes) best electric dps, decent AoE dps with fixed damage from negative charge.
Helps leva get more assists and skill points, very good mobility with teleports. Need andoris to maximize her damage.
At low dupes you can use other dps options if you have them invested (v6 Mosin, v6 Jiangyu).
Needs a bit of dupes to catch up to the other options.
Should I get dupes?
V2 is the breakpoint for low spenders that gives a decent amount of damage, while v3-4 are breakpoints for high spenders which helps her movement, attack range and also gives her ramp up damage for longer fights.
Expansion Key
A nice damage boost while also loosen the requirements to get max damage on her 2nd skill and ultimate.
If you don't like her or not planning to use her that much then this key won't save her in the meta. It's an ok key but nothing crazy.