Off-tank DPS that hates Elite units and provides various benefits. Her damage increase isn't stellar, but she has enough rider effects that you can probably find some use for her. Like C-MS, she can equip AP rounds. YMMV with regard to how useful that is.

So if it hasn't been said enough, absolutely get the Mod1 the very second you can. It's 200 fragments and some cores for a fair boost in performance. Extra stats, a bit more FP buff on her tiles, a little extra HP, and an improvement to the slowdown effect on the smoke.

The real problem is her 2nd skill is janky and not extremely practical. It's a little bit of a bonus, but not likely to make or break a fight. So yeah, the Mod2 isn't great. The mod 3 however, gives her a unique equipment that goes in the suppressor slot and is basically a suppressor with better stats (+5 EVA over normal) which helps her tanking ability somewhat. Whether this is worth it up to you, but definitely get the Mod1 at least.

The rest of this is basically the same song and dance where she has top class offensive buffs that continue to remain unmatched among SMGs, so you WILL likely continue to use her.

Thot twin #3?!

And probably the one that's going to give me a fucking heart attack. Yes, her skill has big numbers. Biiiiig nuuuuuuumbers. Now get your dick off your phone screen and start using your brain:

• If she does not use her active, she slowly gains evasion over time. Emphasis on slowly.
• If she does use her active, her evasion slowly drops down to "nonexistent", making her a sitting duck if she's tanking.

In a proper tanking role, her buff tiles are literally useless: 500% crit buff x 5% SMG base crit rate = 30% crit rate if you aren't running a suppressor or a crit scope, and if you are using those, your SMGs will have shit-tier accuracy even if you stack reasonable amounts of buffs on them. At the same time you're losing out on AR buffs, which will extremely cripple your DPS. You're better off bringing C-MS or RO635 to buff your back line instead. Even Suomi can buff her evasion up faster than UMP40 could ever hope to.

If she does use her active skill, it'll similarly take incredibly long for her to really ramp up her damage skill – at 18+ seconds to get her damage above 2* ARs, she competes with Negev for the title of "slowest stacking skill in the game", and SR-3MP consistently out-DPSes her even without any buffs. With the UMPs' exclusive equip. Without, her damage output is even worse.

You can build some silly 5 SMG meme echelons around her that sometimes don't totally suck, but unless you know what you're doing, you should put her on cafe duty.