In the Otwell Family, it was well known that Robert and William did not get along very well.
Their relationship was complicated, as they were half-brothers sharing the same father — neither too close nor too distant.
Speaking of distance, at the very least, they were further apart than full brothers. Thus, William would not guard against his own brother's descendants, but he would be wary of Robert potentially "overstepping his authority."
Speaking of closeness, if William were to die unexpectedly in war, Robert, leveraging his demigod status and their shared bloodline, was the most likely candidate to seize his position.
Thus, William's stance was clear. The enterprise I built should be inherited by my descendants — you can go carve out your own domain in greater Italy.
In the end, Robert only managed to seize the Calabria Region, barely establishing a foothold for himself.
