The Kuronmeru Clan believed in Survival of the fittest. Most Clan members believed that outsiders or non-clan members had 'filthy blood'. Even within the village of the mist, the blood users did not pay any respect to any individual outside of their kin.
While the Clan specializes itself with the use of Bllood Jutsu, they also hold a very high standard with each member knowing Medical Ninjutsu. For even the strongest fighter in their clan must also know Medical Ninjutsu in order to keep their physical health and ability at its peak.
The Kuronmeru clan started back in the time the first Mizukage was founding the village. A group of ninja specializing medical as well as water based Jutsu, created a small experimental organization. Taking the fake title of a hospital, they were given multiple patients of which they experimented on. It did not take long for the use of Forbidden Jutsu to begin. The hospital they created in time slowly began to act as a sort of Insane Asylum.
Although the original motives for this group of ninja were unknown, it was believed they were attempting to create a new form of a ninja for the mist village. They discovered that through special means some of the patients were able to mix their blood and their chakra and use it similar to water based Jutsu. This result did not last long however as the patients blood began to turn pitch black and poison their bodies.
As the Medical ninja decided the blood jutsu was a waste of time, they had found out that a pregnant patient whose blood had turned black had an offspring that survived within her womb. This little girl within the hospital grew up, with her mothers black blood running freely throughout her veins. They discovered that she was able to perform blood type jutsu even though her blood was completely black.
Overtime the experiments of the blood jutsu continued as they infected the pregnant mothers with the black blood and collected the offspring for more experimentation.
However, in the future the group of Medical Ninja would find there records halted as the Black Blood patients broke out of their confinements and escaped into the village, where they started their own lives and began to reproduce and make their own offspring.
As time passed within the village of the mist, the individuals with black blood moving through their veins joined together and created a clan to bring each other together, and to strengthen their bonds. As ninja's within the clan grew stronger they began to all fight for dominants. Through these fighting they all gathered together and decided that only the strongest should lead the strong.
The Hierarchy of the Kuronmeru clan, held their leaders at the top of the pillar. Once the current leader either passed away or was unable to prove his strength (either due to illness or age) for the group, the clan would gather its genius warriors and battle to decide who was worthy enough to earn the top of the clan.
Age was of no question to them in regards to skill. If a ninja was able to prove their strength and potential leadership, they were given the opportunity to prove it.
Those that did not fight or defend themselves were at the bottom of the Clan. They were considered to be cowardly or weak within the Black Blood Society. At the very least they were expected to learn Medical based Jutsu in order to support the warriors if need be.
The Kuronmeru clan are known for having blackish colored blood, and very pale skin. The Kuronmeru are able to manipulate their own black blood in their bodies. They cannot control any individuals blood that is not their own. This ability allows them to generate excessive amounts of blood and manipulate, animate, solidify and otherwise control it. The density and pressure of the blood being manipulated can be controlled, and be solidified for practical purposes, whether it be to create a wall to obstruct an incoming attack, or create a sort of projectile towards an enemy or target.
They also hold the ability to affect the inside of their bodies due to their blood as well. They can increase their stamina, strength, and speed as well as being able to track objects or living things they place their own blood on.
This is possible by mixing the users chakra with their own blood within their bodies and manipulating it similar to water type based Jutsu. Not only can this potentially put strain on the body but also costs a fair amount of chakra depending on the amount of blood use. The bigger the jutsu, the more blood used.
The use of blood Jutsu is only possible through the use of self mutilation. The wound inflicted cannot be too large since the amount of blood used in the Jutsu must be controlled in order to not suffer excessive blood loss. If the user over exerts themselves in a battle, the result may cause internal damage as well as falling unconscious.
The clan members within the Kuronmeru Clan all have a fair extension of Medical Knowledge. This type of skill helps with the regeneration of blood as well to help the clotting/scarring process in order to use it. The most skilled members of the Kuronmeru clan hold a very unique balance between Medical Jutsu as well as Blood based Jutsu.
It is very common for members of this clan to have a supply of Blood Increasing Pills, as well as Soldier Pills for combat. They also eat very specific foods to help keep energy up as well as blood regeneration in order to avoid suffering cardiac arrest or the sudden slow in blood pressure.