...what about the infants? toddlers? was it to get rid of anyone who could seek revenge?
*The nine familial exterminations- it's essentially executing all relatives of the individual by crime of association. Mainly for crimes that are around treason as generally such a big thing cannot be done by one person and it's more likely that the family were part of it. It's essentially cutting all loose ends and also such a harsh punishment will make people rethink, well… treason. In all fairness it seems like it worked cuz it was a relatively rare punishment (though web novels may say otherwise lol).
[BL] Quick Transmigration: Is it Better to be a Beta?