"Given the targetted decision uses pre-filters, it shouldn't cause a large amount of CPU load, I think."
One method I've been using is to limit the decision to human players and using an on-action event for ai

Thank you for the suggestion. I don't have any plans to make it work in sub-mods at the moment, but it wouldn't be difficult to adapt it to do just that. I always wondered why the game of thrones mod didn't do something similar to what I did here for dragons.

It might take me a while to get around to making a patch for other mods, as I also have other mods of mine I need to update, but if you are interested. Feel free to use the code in this mod to make a patch for mythos.

Incase you are open to suggestions, a mythos patch would be dope. For a dragon ruler to raise dragon raiders for example. Would need some balancing around the combat rating too cause mythos combat rating can escalate rather quickly.

Sorry, I should clarify. It is a minor title, but you can only assign it with the targetted decision. The cleanup should work properly. Whenever a holder of a knight minor title dies or loses their title for any reason, their associated troops get disbanded. I tested a little bit, and that part seems to be working properly so far.

The problem with a minor title is that you can't assign AI weights. At the moment only the player can use the decision, but I intend to allow the AI to use it as well. If I were to use the normal minor title granting mechanism, it would require a very convoluted system to make sure the AI only grants the title to characters that would make decent knights.

The other reason is to make it easier to allow a different number of knights depending on tier. I don't know of any way to restrict the number of knight titles that can be granted based on the tier of the liege, other than making 4 different copies of the knight minor title.

Given the targetted decision uses pre-filters, it shouldn't cause a large amount of CPU load, I think.

Haven't try this but how about change assignment of knights from target_decision to minor_title? It can handle events/flags when a minor_title granted, and cleanup troops when lose it. And it's less CPU occupied.