Aka 64 Shiki if you're a weeb.

She's a bit of a complicated unit in that certain enemy thresholds alter what her skill does, thus making her work better vs bosses (with her colossal 90% FP boost for a few seconds) than for regular encounters. However, the timings are awkwardly short for the big boost, and the 2nd half reduces her firepower a bunch but also buffs the hell out of the stuff in front (which, if it's SR3, means more damage for her.) Note that the skill is less awkward than it seems, as it counts doll groups, rather than individuals, so 5x 5-linked enemies is totally fine, and so on.

Unfortunately, they removed cool tile buff tricks so her potential of giving insane buffs is a lot more limited than before

When her artist read up on her, she was kind of horrified and drew a weak-bodied hospital patient who hates her defective form. In the actual game, she is a good performance AR-buffer. Her skill is somewhat peculiar, because she does not buff herself, but she more than makes up for it by turning the other two ARs into veritable murder machines. Presumably because the other ARs are horrified at the thought of her dying out with them and wanting to kill the enemy as soon as possible.