Type: AR
Rarity: 4
Obtainable from:
Affects SMG, AR, MG
ICD: CD:
[Passive]: When inflicted with an DMG/ROF/EVA/ACC debuff, reduce the corresponding stat of all enemy units by ($dam_rof)%/($dam_rof)%/($eva_acc)%/($eva_acc)% respectively for 3 seconds. After 12 attacks, grant self a debuff that reduces a random stat by 1% for 3 seconds. [Active]: Increase damage taken by all enemy units — Enemy units take an additional +($dam_value) points of damage for every kind of debuff they currently have, lasting ($duration) seconds.
MSBS makes enemies with debuffs take 50 additional Damage per hit per type of debuff currently on them at Skill activation. Note that this is additional Damage, which is applied after Crits, Armor, Vulnerability and Damage Reduction, but not after Force Shields.
While she does reflect debuffs applied to herself back to enemies, this is usually not a reliable way to ensure enemies are debuffed, and you would generally want to bring her together with someone else who applies Debuffs (such as Suomi Mod). Using Suomi Mod as an example here, even if MSBS doesn't apply any debuffs herself, Suomi's 3 debuff types would make enemies take 150 additional Damage from each hit.
While MSBS isn't exactly a general-use AR, she can be useful if you are intending to fight under Parachute Debuff, making even Armored enemies take quite decent damage.
If you intend to use her against Orthrus (which works great), make sure to activate her Skill after the Orthrus Shields activate or the Orthrus "Set Damage taken to 1" will overwrite it. Other similar enemy effects will work similarly.
Additive Damage is completely separate from multiplicative damage buffs, and is applied after Crits, Armor, Vulnerability and Damage Reduction during Damage calculation.
As MSBS isn't especially good at applying debuffs herself, she needs someone else who can reliably apply multiple debuff types on enemies.
While she herself can only apply Damage/RoF/Evasion/Accuracy debuffs, her active Skill checks for far more debuffs than this: DMG, Eva, Acc, RoF, Mov, Crit Rate, Armor, Burning, Stun, Vuln Marker. (Note that this is Vuln Marker, which not all sources of Vulnerability apply, such as Sniper Fairy not applying it.) Similarly, MSBS only checks for multiplicative debuffs. Flat debuffs will not count towards her checks.
As such, if you somehow manage to apply all of these debuffs at once, she'd increase the enemies' Damage taken by at least 500. Of course, it's not viable in realistic scenarios to apply all these debuffs to enemies at once so her actual bonus Damage would usually be a lot lower than that.
MSBS's +50 Damage per debuff type updates in real time, so applying more debuffs after MSBS has activated will increase the damage taken by enemies. Similarly, if debuffs fall off before MSBS's effect ends, the damage taken increase will drop.