FO-12

Overview

FO-12 builds up Activity stacks as she hits enemies with attacks. This counts every hit from her Dummy-links, but misses do not count. When she reaches 100 stacks, she will execute the highest-Damage non-elite enemy in range, after which she will never reload again until the end of the battle as well as setting her RoF to 1 attack per second and increase her Damage a bit. Most highest-Damage enemies in the game are either support units or very deadly units, meaning that FO-12 can eliminate a key target early in a battle, making the rest of the fight much more managable.

Take note that the only thing that scales with Skill Levels for FO-12 is her Damage self-buff, which is largely irrelevant. As such, she can be safely kept at SL1.

Her passive makes it so that all attacks are surehit and increases her knockback chance to 10% if she has another SG in the same column at the start of the battle (you can move her out of harm's way after the battle starts). As both her stacks and being able to knockback relies on actually hitting things in the first place, these effects are both quite welcome. Normal SG knockback chance is 5%, and note that these chances are per-link and are affected by Accuracy. As such, FO-12 is absolutely incredible at knocking enemies back.

The execute works similarly to Gepard M1's Mod, in that it deals a fixed massive amount of damage up to 5 times based on links. This means that if the enemy has enough Force Shields or other Damage Reduction (like Orthrus shields), they can survive the execute. Of course, for the vast majority of content this is entirely irrelevant and you're more likely to be annoyed by the non-elite clause.

Strengths

Execute Highest-Damage Non-Elite

Once she reaches 100 stacks, FO-12 will execute the highest-Damage non-elite target, earning her the moniker SG Grape. This is quite useful to pick off a key enemy target.

Lots of Knockbacks

With a 10% chance to knockback per dummy-link, surehit and not needing to reload, FO-12 will knockback enemies a lot more frequently than other SGs with her normal attacks.

Doesn't Require Skill Levels

As she does her job perfectly well at SL1, she does not need to be Skill Trained at all.

Weaknesses

Not a Tank

As FO-12 is not a tank, she needs to be kept out of harm's way as any other DPS. This means she may need to be kited to safety, losing links is very bad as both her knockbacks and stack rate take a penalty from this. She should be using a Birdshot so she doesn't have the damage reduction from Flash ammo. And finally, she is a SG and her Move Speed is very low.

Needs a Second SG for Passives

To gain her knockback chance increase and surehit, FO-12 needs to start the battle in the same column as another SG, limiting teambuilding and formation somewhat.

Cannot Forced Manual

If you wish to delay her execute to hit a specific target, you will have to kite her.

Full Analysis

Against some enemy teams, the target you want to execute won't get in range until long after the stacks reach 100, and as you cannot Forced Manual her to delay it in an easy manner, you will have to resort to kiting to delay the activation. This is most easily done by letting her shoot her final shot that will make her reach 100 stacks, and immediately start kiting her. She will then instantly perform her execute when she stops moving again.