Getting ideas for a sibling couple who were separated as kids and reunite later in life...
Maybe a minor lord was notorious for illicit affairs, and swept the problem under the rug by exiling his illegitimate kids, or keeping them on as servants to the rest of the family. I'm picturing it in the Caribbean toward the end of British rule but really it could be any historical or fantasy setting.
Once the old man passes on, the family summons his heirs to determine who will be his inheritor. But many of the elder sons have died in service to the empire or acquired their own, more profitable holdings, and are little interested in their father's estate. The only one who shows interest is his youngest, bastard son, whose mother was a lowly servant and who was sent away to a remote posting when he was just a boy. Seeing this as his chance to move up in the world, he seizes his chance.
The family give him a rather frosty reception, but with no other claimants available, they produce the will and start proceedings over the next few days. The only one genuinely friendly to him is the household's maid. Unbeknownst to him, she was another of the lord's extramarital sires, though they were never informed of this relationship as children. She was brought up as a servant, not knowing who her father was, and only finding out after his death.
Given that this is her half brother, and he's also been ostracized by the rest of the family, she takes an immediate liking to him and starts doing whatever she can to help his cause. Their relationship quickly blossoms and he soon falls for her, while she can't find the right time to tell him their true relationship. Anyway, at some point she feels like she can't keep it secret any longer (maybe after the first time they have sex lol) and she confesses to him. He's understandably freaked out but takes it better than she expected.
Hijinks ensue, the rest of the family start scheming, maybe he duels one of his half brothers who returned when he heard there was a rival for the inheritance. When all's said and done, he returns to his sister, mind made up, and declares that blast it, having the same father won't make him love her any less. And they live happily ever after. ♡
