I generalize this here a bit more, than maybe other sites / people do, but here I mean everything, where the character either gets hypnotized, actually mind controlled, or somehow else gets their sense of self actively altered.
Metal Lovers by Master-Geass
Metal Lovers by Master-Geass Another absolutely fantastic mechanization story by Master-Geass that follows Arij fulfilling one of her and her roommate Nozuru’s dreams by buying a very advanced drone / robot suit. Both had been very interested in drones and had quite some kinky fantasies about what they’d do with it. With Arij secretly buying such a suit, she begins getting dressed in it as a surprise for Nozuru, but messes up the initial settings and gets eventually trapped inside it. Once she had finished dressing, the suit got activated and took over all her functions and began filling her mind with all the tasks and data she needed to know, while fully transforming her into an obedient drone. Hoping Nozuru would eventually free her, once she came back home, except that her roommate has quite some other ideas with her new robot partner. ...