Succession Rage

[BigBadYoda]

So, I play Ivar and I am ONE county away from "King of all the Isles" and Ivar kicks the bucket. He has ONE grand child that is set to inherit ALL kingdoms but for whatever effing reason, some of the duchies go to the king of Sweden who is also a grand child of his. What mechanic is that and how the flying fudge can you prevent that?

[Emperor2000]

Originally posted by BigBadYoda:

So, I play Ivar and I am ONE county away from "King of all the Isles" and Ivar kicks the bucket. He has ONE grand child that is set to inherit ALL kingdoms but for whatever effing reason, some of the duchies go to the king of Sweden who is also a grand child of his. What mechanic is that and how the flying fudge can you prevent that?

Grandchilds replace their dead Parent in the Succession Case.

They even get their Parent's implicit Claims.

[BigBadYoda]

Originally posted by Emperor2000:

Originally posted by BigBadYoda:

So, I play Ivar and I am ONE county away from "King of all the Isles" and Ivar kicks the bucket. He has ONE grand child that is set to inherit ALL kingdoms but for whatever effing reason, some of the duchies go to the king of Sweden who is also a grand child of his. What mechanic is that and how the flying fudge can you prevent that?

Grandchilds replace their dead Parent in the Succession Case.

They even get their Parent's implicit Claims.

Yes but those are vassals in my kingdoms that all of a sudden are in the Swedish kingdom. it makes no sense, why would individual vassals move over to another liege on succession?

[Emperor2000]

Originally posted by BigBadYoda:

Originally posted by Emperor2000:

Grandchilds replace their dead Parent in the Succession Case.

They even get their Parent's implicit Claims.

Yes but those are vassals in my kingdoms that all of a sudden are in the Swedish kingdom. it makes no sense, why would individual vassals move over to another liege on succession?

Elective Title Laws on the Titles?, because Vassals under Elective Laws, swear fealty to the Title and not to you personnally.

[BigBadYoda]

Originally posted by Emperor2000:

Originally posted by BigBadYoda:

Yes but those are vassals in my kingdoms that all of a sudden are in the Swedish kingdom. it makes no sense, why would individual vassals move over to another liege on succession?

Elective Title Laws on the Titles?, because Vassals under Elective Laws, swear fealty to the Title and not to you personnally.

Nope, for example: I just ran it again from a save point. Iceland -> Norway Kingdom, right. Goes to Sweden. Kingdom of Norway is held buy the King of Denmark. MAKES NO ♥♥♥♥♥♥♥ SENSE!
Greek Islands, Go to the Swedish king who has NO ♥♥♥♥♥♥♥ DOG IN THE FIGHT DOWN THERE!

[BigBadYoda]

So, here is the ChatGPT answer:

In Crusader Kings 3, vassals switching allegiance to another king despite your control of multiple kingdoms is usually due to one or more of the following factors:

1. De Jure Drift and Liege Priority
If a kingdom title is not the de jure liege of a duchy, vassals might prefer to swear allegiance to the ruler of the de jure kingdom rather than remain under a de facto ruler.
In your example, the Duchy of Iceland is de jure part of the Kingdom of Norway. If the King of Sweden somehow holds the Kingdom of Norway title (or it has de jure drifted towards Sweden), the Duke of Iceland might decide to become his vassal.
2. Crown Authority
If your Crown Authority is below Level 3, powerful vassals can freely switch allegiance to a different liege if they share a higher-tier title (e.g., a duke might choose to serve another king if he prefers them).
If the King of Sweden has higher Crown Authority than the King of Denmark/Norway, Iceland's duke might choose Sweden instead.
3. Cultural & Religious Differences
If the Duke of Iceland shares a culture or religion with the King of Sweden but not with you, he might prefer to be under Sweden.
This is more likely if you have a different faith or if Sweden’s king is actively promoting his culture/religion in Iceland.
4. Opinion and Strength of Sweden
If the Duke of Iceland dislikes you but has a high opinion of the King of Sweden, he might choose to become Sweden's vassal.
If Sweden is particularly powerful or holds de jure Norway, Iceland’s duke may see Sweden as a more stable or beneficial liege.
5. War and Rebellion
If you were recently in a war or a succession crisis, vassals might take advantage of the instability to change allegiance.
If you were weakened, the Duke of Iceland might have negotiated to become a vassal of Sweden instead.
6. Title Loss on Inheritance (Gavelkind/Partition)
Since you mentioned all your kingdoms have one heir, it doesn’t seem like inheritance split caused this. However, check if a different relative inherited something that could have caused a shift in vassalage.
How to Prevent This?
Increase your Crown Authority to Level 3 or 4.
Improve your vassals' opinion of you.
Ensure your primary title is the de jure liege of important vassals.
If possible, integrate de jure lands using the Chancellor’s task "Integrate Title".
Avoid vassals with strong claims on other kingdoms or dynastic ties to rival rulers.

In a nutshell, I am effed because I only have crown authority 2. I just save scummed and killed the king of sweden and now my opinion 100 vassals swear allegiance to the king of Finland. ♥♥♥♥ THIS GAME. I'M OUT
The ♥♥♥♥♥♥♥ duke of the Aegean Islands swears allegiance to the King of Finland. This is ♥♥♥♥♥♥♥ stupid. If the Duke of Gotaland does that, fine, but not the Dukes in Italy and Greece. And also, I don't know where the hell ChatGPT gets the info, but the fact that crown auth 1 and 2 allow Dukes that are not under a de jure Kingdom can swear allegiance to who the ♥♥♥♥ ever is documented nowhere.

EDIT
It is not even counties with no de jure kingdom - quickly created the Kingdom of Sicily and even then I ♥♥♥♥♥♥♥ lose the vassals there! THIS IS ♥♥♥♥♥♥♥ ♥♥♥♥♥♥♥♥

[meraco]

I love mods.

The following solved your issue for me.
Just make sure your playing a feudal nation.

https://steamcommunity.com/sharedfiles/filedetails/?id=2218549875