Nameless Worm

Nameless Worm are the parasitic worms that inhabit the bodies of the Deadmen.

History
The worms were originally created by Sorae Igarashi and Hagire Rinichirō. Together, they studied different ways of heightening a person's immune abilities. The pair used several guinea pigs including Shiro for such experiments. Their existence was determined to be a byproduct of the pair's research.

Due to the Great Tokyo Earthquake, the worms were spread throughout Tokyo.

Effects of the Worms
Once inside a human, the Nameless Worm integrates with their body, permanently altering them. When this occurs, the individual is then referred to as a Deadman.

Most Deadmen were infected during the Great Tokyo Earthquake, however, there are exceptions such as Ganta Igarashi, who was infected by the Wretched Egg during the Nagano School Massacre.

Overview
The Branch of Sin (罪の枝, Tsumi no Eda) sometimes abbreviated as BoS is the ability to control and freely move the user's own blood outside of their body as an extension of oneself. Those who possess a Branch of Sin are known as Deadmen.

The Branch of Sin can be formed into various shapes and objects and is often used as weapons. Their powers and shapes vary and are unique to every Deadman. This power was created by the Nameless Worm carried by the Red Diamond. To summon their power, they first need to inflict at least a small abrasion in order to draw the blood out of their body. The blood they extract appears as a sort of string that's directly connected to their veins and arteries, which can be restored afterward if it's still connected to them. In very few cases, the user can completely control their blood while it's not directly linked to them and can even reuse the blood to recreate their weapon/s. In a case where a Deadman sustains minor wounds, they can slow down their blood or halt it at certain portions of their body to prevent themselves from bleeding out.

It's unclear if Branches of Sin manifest a unique power on their own or if they adapt to the Deadmen's genetic and biological characteristics. Whatever the case, all Deadmen, with enough practice, have been known to master their abilities over time. While using their abilities, hexagonal plates of unknown material appear, either embedded inside the Branch itself or floating around it in a circular motion. The Branches can be long range, close range or both. Long range Branches can either be thrown, shot, or extended to reach their opponents at a certain distance, while close range Branches are bound to close quarters combat. Deadmen can use more blood in order to reinforce their Branches ability, as well as increase their size or lengthen them if required. The two main disadvantages to this ability are anemia and Worm Eaters. Even though anemia is common for those who use long range Branches, many Deadmen have been known to overcome it.

In the anime, Branches of Sin intend to stray from their original look. They also appear to be more liquefied than fully solid and constantly change shape during their forming, as it is with Ganta's bullets, from round to elliptical and Senji's blades, from curvy to straight.

Unison
It appears that at least two Branches of Sin can be combined by mixing the blood of two Deadmen while forming their weapons to create a more powerful version of their Branch of Sin that consists of both of their abilities. This has only been used once by Chaplin Sukegawa and Minatsuki in their battle against Uzume Sumeragi.

Supersonic
Certain Branches of Sin have been developed to the point they exceed the speed of sound by breaking the sound barrier. This ability increases the speed of one's own power, enabling it to cut or pierce through enemies and solid objects, as well as easily overpowering Worm Eaters.

Despite the lack in power, less blood is utilized, preventing users from falling victim to anemia as quickly. The only Deadmen to achieve this ability are Ganta Igarashi and Kiyomasa Senji. In the anime, Minatsuki Takami and Hagire Rinichirō (While possessing Toto Sakagami's body) are also able to make use of this ability.

To achieve this ability, different methods are applied to each Branch. Ganta makes his bullets smaller and slimmer, focusing more power into the blast and Senji makes his blade thinner, being able to draw it out much faster.

Evolution
Branches of Sin can evolve over time, for example, Ganta's Ganbare gun and Senji's unnamed evolved Crow Claw. These evolutions have occurred due to their strong will to live and high determination, eventually leading to their newfound abilities. Evolved versions don't stray too far from their original powers and appearance. Patterned, black lines (shiny red-pink in the anime) appear on Deadmen when using an evolved Branch of Sin. These marks usually appear near their Branch of Sin's manifest points. The Wretched Egg's marks cover her entire body when her full power awakened. Their appearance is distinct for every Deadman, from straight patterns, to curly lines.

The main disadvantage to this ability is that it uses a large amount of blood and places strain on the body. Overusing it will cause burns and scars where the marks appear, all the way to the location of the red crystal inside the Deadman's body.

Synthetic Copies
Tsunenaga Tamaki was able create artificial Deadmen called Forgeries. They possess the abilities of Deadman as well as a poison (carried in their Branch of Sin) designed to give them an advantage over Deadmen. The Forgeries are forced to wear masks that not only induce brainwashing effects but cause the wearer to remain in a heightened, euphoric state.

Their elite troops are called Complete Forgeries.

Removal
A Worm Eater is a device that instantly oxidizes the Nameless Worm residing in the Branch of Sin. With the Nameless Worm gone, a Deadman's blood becomes useless.

The Worm Eater was invented by Tsunenaga Tamaki and was given to the Undertakers. It has been effective against every Branch of Sin except for evolved variants.

The only way to counter a Worm Eater with a regular Branch of Sin is to attack with the speed of sound, breaking the sound barrier, like Senji's Invisible Black and Ganta's Supersonic Ganta Gun.