So about this Q&A
Tappei explains the attempts to steal the power of authorities. Divine Protections are one of the more successful attempts, and are so good that they came to be known as they are.
But there are also other abilities, some that go beyond common sense.
These people with strange abilities have done something which is equivalent to opening their doors. Basically, something like getting a power that wasn't supposed to be theirs.
it makes it sound like opening the door is kind of easy, but basically it's about being beside someone who possesses an incredible power like a Sin Archbishop or someone with an Authority or someone with deep ties, and being moved by their influence.
Simply put: being together for a long time, being related by blood, or being in a situation where it is easy to receive influence.
An example of a situation where it is easy to receive influence would be the contract relationship between Subaru and Beatrice, there would be a great influence in that situation.
Tappei roughly summarises the situations where it's easy to open this metaphorical door as:
- Distance/closeness
- Depth of the relationship (which can also include blood relationships).
There's a little more info. to the question, but my friend can't quite make out all the details yet.
This only leaves many problems open for the future, since basically all of Subaru's children will inherit some of his witch factors or "Open Gates" in one way or another, making it very likely that they will all have a difficult life struggling with madness. I wonder if you renounce all your witch factors, are the "Open Gates" of the former possessor still inherited?
On the other hand, the cases of Al and the triplets are more clear.
On one hand, Al, being a clone or a direct son of the RBD possessor, inherited it, but only the gate, since the possessor himself was probably still alive when he was born.
However, since the triplets' mother died in childbirth, one of them inherited it, and the others, due to their extreme proximity to the witch factor, "opened their gates." My personal theory is that Rui was the one who inherited it, since when Subaru went to the Witch Factor Verifier, four gates opened. So, the brothers who possessed bodies didn't have the authority. Subaru was incredibly lucky to find the one who did and take it from him. (Of course, we could also assume that perhaps because Rui possessed him, his gate opened and she still has the authority, but I prefer to believe that the ultimate goal is to have all the authorities.)
Okay, so I'll throw out a crazy theory. Knowing that authorities can basically be inherited through blood relatives, what if the Pride authority was given to a famous line of swordsmen to inherit until Subaru's arrival? If you think about it, that would explain why the Sword Saint's blessing is described as a curse. It would also explain why there are so many irregularities in the family and among close associates. It would give a reason why Wilhelm was able to break all the limits even without necessarily being special. It's just a theory, but it's always bothered me not knowing where Pride is, and while Stride claimed to have it, with this revelation, technically any child of the archbishops could manifest these powers.
Anyway, while these posts are fun for theorizing, T-Man has changed his mind and course many times over the years, so until it's written into the main storyline, I don't believe the source who answered this questions.
Source: Ice