A noble is an NPC person who governs a settlement and possibly a realm in Spirit Land.
A noble belongs to a dynasty which specifically doesn't belong to a player.
Progression
A noble starts at level 1 and gains prestige with its settlement interactions.
After gaining enough prestige the noble levels up and will unlock new abilities.
When the noble gains prestige an equal amount is added to its dynasty.
Also when gaining prestige the noble also gains influence which is used to perform actions towards other nobles, realms or world entities.
Influence gained is increased as the noble levels up, making it faster to build up even if prestige gains are not increasing.
Turn Jobs
As states in the game time document, each real-time hour is considered a game-day or a turn.
Each turn nobles with enough influence will try to act following this logic:
An unmarried noble will try to marry
A noble with no free child will try to have a child
A noble with a free child will try to claim land for it
Marriage
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Diplomacy - Not Implemented Yet
Nobles can have relations between them, measured by opinion values towards each other.
Since each noble can be influenced by the environment, personal taste and recipient attributes, the two nobles in a relation might have (and probably will have) different opinion levels towards each other.
Some opinion modifiers are statically bound to permanent trait and will remain until that condition persists.
Some opinion modifiers are tied to events or rumors or spot behaviours and will decay over time.