Character
Secretive and vague. Assumes all knowledge is harmful as a default with very few exceptions.
They will only share knowledge under the idea that who they're sharing them with will not tell anyone else what they had heard.
Those who wish to know their secrets must tell no one of what they've learned, and if they do, they will be made to suffer for it.
They must be dissuaded from saying anything more, after all. It could put people in danger if they do.