Wendy is unusable entirely without insane babying. There are enemies (several Archers and I think all Mages) that ORKO her. Literally every enemy except maybe Thieves 2RKO her. She does no damage (something like 8 hits to kill Archers) unless you give her a stronger weapon (I don't know if she has the rank for it or not), but then she weighs herself down and now everything other than Soldiers and Knights get to ORKO her, and her accuracy is shaky as hell, and she still does **** damage. There's seriously no way to have her be good without deliberately setting out to try to make it happen, because she's incapable of contributing whatsoever on her own.
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Mistake you're making - overlooking the fact that we might not want to be saved.