You could mimic a feat try by having it a feat to start and then you gain abilities with levels after you took it. So, if you take it at level four, you have four levels of the feat by level 8 where someone who just took the feat would just be starting out.
Still working on Blood Magic. It had several levels of power, i.e cannibalize your hp for metamagic, at higher levels take the hp from unwilling sacrifices. etc etc. Not looking for feedback on Blood Magic itself (yet). But rather feedback on how to implement such a concept. I guess the main thing I was concerned about was having i.e. all kinds of blood magic npcs and villains, and eventually a PC takes the feat and boom, even though he just took the feat, he has all the "higher level" abilities.
Even if you are a fighter who gains a level of wizard, you dont go straight to 9th level spells. See my thoughts?
I was going to go with either paring the feat down to its basic theme (keeping it simple 5e style) like [MENTION=92511]steeldragons[/MENTION] suggested.
Or...go with what Ahrimon mentions...thoughts?