Okay, so here's the deal; every time dragon blood is shed, it hardens on contact with the air, forming crystals of 'bloodstone.' Bloodstones are infused with the magical essence of the dragon it originates from, and due to humanity's connection to the Earth element, they can absorb bloodstone and by extension, it's magical properties.
However, there is a caveat; only two kinds of people can absorb bloodstone. Those who have slain a dragon, and those who have been eaten by a dragon. When someone slays (or grievously injures) a dragon, magical energy is released, "marking" them and forming a (rather dark) connection. Similarly, since digestion forms a link (you are what you eat has some basis in fact in this world, for reasons I will not disclose unless necessary to avoid erecting a wall of text), those who have been inside a dragon and subjected to its "juices" have a connection to that dragon.
Only people who have slain (or grievously injured) a dragon, or been eaten by him or her, can absorb his/her bloodstone. After one ingests bloodstone, they are enchanted, gaining special abilities; bloodstone from a Sky Dragon allows one to fly and manipulate the wind, bloodstone from a Fire Dragon makes one fireproof and allows them to manipulate fire, and so on.
Bloodstone consumers are also enhanced; not only do they gain greater energy and stamina, but their senses, strength, speed, (as well as their survival and combat skills) are all enhanced. The level of these enhancements depends on the dragon's power, as well as its type; Fire Dragon Bloodstone grants greater strength than anything else, while Sky Dragon Bloodstone grants greater speed than anything else.
However, two problems have convinced me that I need to put checks on this. Number one, there's nothing stopping a Dragonslayer from slaying dragon after dragon, gaining more and more power each time, or a reckless (or rather smart but unconventional) princess from going out and getting eaten by dragons and eating their bloodstone after they've been slain.
Number two, bloodstone can only be absorbed by those connected to a dragon because of the species gap. However, after being infused with draconic energy through bloodstone ingestion, humans generate bloodstone naturally (AKA just like dragons do). This bloodstone can be absorbed by blood relatives (siblings, parents, children) or anyone who manages to grievously injure or kill that individual.
Considering the two above factors, my question is: How Can Bloodstones Be Better Balanced To Avoid Creating Overpowered Individuals Or Increased Murderousness In Society?
**Please Note:**If at possible, I would like a balance method that allows someone to absorb more than one bloodstone while preventing them from becoming godlike through sheer number of absorbed bloodstones. This is because some ancient dragons, lying dormant far away from civilization, are so powerful that if they awakened there needs to be dragonslayers capable of handling them. However, no one dragon in the current age holds enough power to create such a dragonslayer.
Thank you for your input and feedback, I truly do appreciate it. If you choose to VTC or downvote, please give me an explanation so I can improve this question and post better ones in the future.