So, while checking the page about current Dead Apostles, I was having trouble to kinda get how their ranking works. Like, I get it's also about potential or being Rank III slave but how do you EXACTLY rise it? Do you just need to drink enough blood or do you need to understand/develop that "curse" more?

Also what is that "curse?" Is it about their Idea Blood/Principle or something else because I re-read the page like 2 times and still couldn't see the explanation. So either I was and am right now too sleepy/tired to notice or idk.