it's possible for the king/vice king to delete their accounts if they request deletion of all their data as per the GDPR regulations. Once the data is deleted their account along with all achievements, prestige, Gold and existing game world avatars are also gone. I'm sorry for the inconvenience caused but unfortunately we are unable to restore any lost treasures in such cases. Please note that kingdom unions are an important commitment and should only be formed with trustworthy players.
Seem like a fault in the system to me, that such an action is made before all game avatars are deleted or even eligible to delete.
In my opinion, if a player were to do this. Their game avatars should stay for 72 hours as an inactive dummy and treasuries should be deactivated.
The unions should only be founded by trustworthy players, but you do not really know how their gears flow before they've have properly grinded. And as this is an online game it is hard to know everyone to that extend. Some kids will never grow up.