Various ways to look at power.
“vassals are also not vassals to a title but to a person; a duke with two ducal titles who is deprived of one loses no vassals because they do not belong to the title, but rather to the duke. This is such an enormous, fundamental difference between the way CK3 works compared to other strategy games that I really want to spell it out again: CK3‘s political world consists of rulers not of kingdoms or lands or countries.”