Notes

The married warlords who never met each other and became close friends through frequent letter exchange. United their states together in harmony. Ironically, their reign would probably not be as great had they met and settled, as they'll be trapped in an unhappy marriage.
This does bring up a lot of problems for when their child (conceived with other people) comes to succeed them. Do they convince others that they're legitimate, despite their parents never having met?
One reasoning: the mother drank from a river that crossed both of their territories
Will the Pendiri house consider them non-people for being born between people who are not married?
Ultra sinful for conceiving with people who are not your partners???

the married-but-never-met warlords both had posas blood (unknowingly) and were expected to conceive children. because they had children with others, they effectively tainted the potency of the posas blood line and their children turned out weaker.

while the main posas heir had Lorenzo's genetic disease manifest badly and died early, the illegitimate child did not want to continue the posas reign, and then had to prove WHY they WERE illegitimate.