Partes da sua descrição soam como "Spook", um conto de Bruce Sterling (publicado no "Crystal Express" com várias outras histórias de Shaper / Mechanist e algumas histórias de fantasia).
Estou com preguiça de ir buscar minha cópia, um resumo on-line diz que
In "Spook," the earth has suffered a "brain drain" through mass emigrations to space leaving a world populated mainly with "undesirables." The powers-diat-be have their hands full trying to maintain a semblance of order and control; faced with a potential uprising in Central America, they contract the services of a futuristic secret agent - the "spook" of the title - to quell the insurgency. The denouement to this space-age thriller is devasting.
O fantasma tem algum tipo de implante que reprime sua memória e a maior parte de seus sentimentos. Ele está infectado com um vírus sob medida e vai para a selva para lidar com uma revolta popular que ameaça as poderosas corporações. Lá,
he runs into another spook who's had her implant removed. She gets the drop on him, they remove his implant and when he wakes up in a hospital he remembers other assignments he's been sent on where he was basically programmed to massacre groups the corporations don't like. He appears to be on his way to joining the insurgency.
Então a história pula para o fantasma estar de volta ao escritório do cara que o enviou, explicando o que aconteceu e aconteceu,
that despite having the implant removed, he still wipes out everyone involved in the uprising because he's too far gone and wants the implant back so he can stop feeling and remembering things. (I don't know if devestating is the word I'd use, but there is a pretty awesome twist in the story that I haven't included.)