General overview

Cutter packs a huge punch for her rarity. She's one of the few melee units who can hit drones, and her kit has options for single- and multi-target damage. Her main downside is that she has to constantly attack to charge SP, which is usually only possible if you have her directly taking hits (a difficult proposition, with her mediocre defensive stats). She also has no way of attacking drones outside of her skill, unlike archetypes like ranged guards, who can target them with normal attacks. These downsides shouldn't overshadow the fact that she's an incredibly strong unit with DPS that's comparable to her higher rarity counterparts.

E2? You should E2 her. It's cheap, and she gets a lot out of masteries and her module.

Talents

Cutter's talent gives her normal attacks a chance to restore 1 additional SP. This is very useful because she can only charge her skills by attacking.

Skills

S1 (Redshift) attacks random enemies within range (Lord range) 4 times. The 4 attacks are done consecutively, and targets are selected with each attack. If something walks into range while she's unloading her skill, it counts as a potential target. This skill is best used when you're positive that she's only going to hit one enemy because she'll maximize her damage that way. You might have to face her in a weird direction to guarantee that she hits her intended target.

Conversely, S2 (Crimson Crescent) hits 6 enemies in range (Bard range), with double damage against drones. This skill is kind of wasted if you only use it on one or two enemies, so it's the reverse of S1 in that sense. The drone damage is ridiculous, and she'll often kill them this way. You do need to be a bit judicious with it if she's not attacking and charging SP constantly, as she can't attack drones otherwise.

Masteries

Both skills gain a lot from masteries and are very cheap since she's a 4 star. Which one you prioritize depends on your play style.

Modules

Module Y has Cutter ignore 70 enemy DEF, which essentially translates into a 70 ATK buff for her (on top of the buff she gets just from having the module). Mod3 increases her talent SP RNG by 10%, which is huge. If you use her, there's no reason not to get her module.