I haven't seen the event in a while, but I am pretty sure that it disinherited your current primary heir if you choose that option.i didnt think it did? i think ive gotten a designated heir without that happening. i know that one even is due to my heir doing something bad but i thought there was another version? (one my kid was a sadist blademaster and killed someone and laughed about it, went around being a "duelist" and just straight up murdered people)