Responses
Apparently that wicked hag of a “mother” poisoned the boys birth mom, which is why she died during child birth and why his hair isn’t the same color as the dukes. Nobody thought he was the dukes kid and that evil woman wanted to keep it like that, thankfully she failed. Sadly the kid was still pretty abused by the time the info was discovered.
Per my understanding they aren’t half siblings, or genetic siblings, technically they were step siblings. TECHNICALLY
Blondie at one point says that her mother brought her to the house and that the duke isn’t her father. The duke didn’t know the chained up boy was his son but the red haired bitch did know. So on a technical legal stance, because the red haired woman was married to the duke, that made blondie and black haired boy step siblings.
Since the mother is no longer married to the duke, blondie and black haired boy are not really step siblings anymore.