Read first, post later
Sorry, but the Marius reform is called "The New Man", so I confused it. Still, the answer remains, yes, it´s hardcoded, and as Epistolary Richard said, it depends on how many settlements and family members you´ve got. It´s the game´s way of making sure you can´t lose since when you run low on family members you can adopt a captain . The same goes for the AI as well, by the way, making the try to use assasins to take out a faction a pain in the back.