Gavelkind + childless succession question

[Elenhil]

I have once managed to inherit a duchy when the relative holding it died childless. Now that I am trying to recreate it elsewhere I do not succeed at all: there's a relative, he has a son and a sister, but when he dies the line of succession looks like 1) son, 2) sister, 3) an endless line of people from a totally different House. Now, what are they doing there? Admittedly, they are not totally alien - their House did rule the duchy before I sneaked my blood in. But that is the general primciple of who succeeds a childless ruler with gavelkind?

[Gemberkoekje]

Have a good look at the relatives tree and you can probably figure it out.

I'm not entirely sure what takes precedent, but it's the closest living relative as far as i know, and I think nephews/nieces take precedence above aunts/uncles, and they take precedence over further relatives. If there are no relatives, any higher power will inherit the land (Dutchies of HRE could pass to the emperor this way) - I'm not quite sure what happens if an independent house dies out, but I can imagine counts becoming independent if it's a dutchy, and barons taking over as count if nothing else is available.

[TehJumpingJawa]

I have once managed to inherit a duchy when the relative holding it died childless. Now that I am trying to recreate it elsewhere I do not succeed at all: there's a relative, he has a son and a sister, but when he dies the line of succession looks like 1) son, 2) sister, 3) an endless line of people from a totally different House. Now, what are they doing there? Admittedly, they are not totally alien - their House did rule the duchy before I sneaked my blood in. But that is the general primciple of who succeeds a childless ruler with gavelkind?

Without seeing the family tree, I'd guess that the sister is married (not matrilineally) to this 'totally different house', and she has a child heir.

[Elenhil]

No, neither child is married. However, the 'totally different house' is, in fact, his father's (I am related on their mother's side, matrilinear marriage). So if his children die childless their grandfather's relatives are to take over. The questions is: in what circumstances it is me, not 'them'? When I am a closer relative of these children than they are?

Or, rather, which indirect relative generally succeeds a childless ruler?

[perpetualmuse]

I am related on their mother's side, matrilinear marriage

I think this is your problem. The inheritance algorithm is looking for relatives on the father's side first and then branching down that family tree.

[GamingHUD]

No, neither child is married. However, the 'totally different house' is, in fact, his father's (I am related on their mother's side, matrilinear marriage). So if his children die childless their grandfather's relatives are to take over. The questions is: in what circumstances it is me, not 'them'? When I am a closer relative of these children than they are?

Or, rather, which indirect relative generally succeeds a childless ruler?

The simplest solution*: keep killing them off until you are the legitimate heir.

*Not necessarily the simplest solution as advertised.

[Osgarl]

Just ran into a similar situation. I use cognatic gavelkind for fun (with CK2+) and my main heir was my first daughter, she only had 1 son before she died. Wen I finally kicked the bucket and the son became a child duke his father and his family are suddenly my heirs. Daddy is quite ambitious too so I may have to exterminate some pests...

[Elenhil]

I wonder if the algorithm would prefer a female relative of that tree over a male one of my Dynasty (me)?..

[Osgarl]

Well it seems only my dear daddy had to die to fix my inheritance. Shame though, he was a great chancellor.