I know this may not catch many interest but I'd like to try anyway.
The basic idea is master and slave, but this is a bit different. The master surely is the dom, asking her to call him sir and beg for permission to cum but not like those would call her a bitch/slut and make her laid with another man or woman. He cares for her and loves her. This could go two ways:
-He has grown up in a society where men own women so the way he shows his attention to her is different. He hasn't thought about having a slave until he meets her. In this version the female character would be quiet a rebel, fighting him at every opportunity, hating the idea of her being a slave.
-She is born a slave and is given to him. She has never since herself different and doesn't know what to do if she's "free". He could set her free but she would cling to him and beg to stay, thinking that he doesn't like her. He would have to work hard to teach her being a real independent human again.
The slave's personality would be different in two version, but eventually she would fall in love with him and we could discuss what would happen after that.
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