Doll

Dolls romanized as (doru), are the Bount equivalent of a Shinigami Zanpakutō. Like a Zanpakutō, a doll is its creator's power given physical form. Also like a Zanpakutō, a doll's personality is much like its creator's, though the dolls seem to have more personality variation than the Zanpakutō spirits seen thus far.

Overview
The main difference between a doll and a Zanpakutō is how they operate. Unlike a Zanpakutō, whose personality is generally dormant except when the Shinigami wishes to speak to them, a doll's personality is always dominant. Dolls are self-sufficient when released, though they can easily be resealed. The Bount's ability to control their doll is largely based on their individual power and relationship with the doll. Moreover, if either the doll or its Bount partner sustains severe damage in a battle, the Bount may lose control over his doll, depending on the amount of damage dealt. If a doll is injured, it will simply return itself to its sealed state. However, should its master be injured, the doll may go berserk and kill its master, as Ugaki and Mabashi's dolls did. A doll may also kill a Bount who is not powerful enough to contain it, as was the case with Cain. Bounts with a genuine bond with their dolls can transgress this (but only if their interaction goes well beyond that of between master and slave), however, as shown by Yoshino Sōma's doll's loyalty towards his master to the point where he refused to leave her side to fulfil her final wish: for her to be merged with him.

Like a Zanpakutō, dolls are generally sealed into an object and released as necessary (Gō Koga's doll, for example, is sealed into a metal sphere). The object varies greatly from person to person and is often an expression of the doll's abilities. In order to call upon a Bount's doll, the phrase "Zeige Dich" is said, which is a German phrase meaning "Show yourself."

To summon a doll, a Bount needs to undergo a ritual where they chant an incantation. These instructions were first given to young Jin Kariya by Ran'Tao after the Shinigami attack. The ritual includes sulfur, phosphorus, carbon, water, fat, magnesium and lime (the ingredients of the human body). When a doll is summoned, it is small in size and power, but grows as the Bount's power grows.

Some Bounts, including Gō Koga, and Ryō Utagawa have the ability to transform their doll into a more conventional weapon, such as an axe, or a whip. This ability is not the same as Yoshi's doll Nieder, which has two weapons as its normal form.

Bitto
Jin Kariya and Ugaki were also able to create a unique form of dolls known as the bitto. The bitto are mosquito-like beings which drain the souls from humans and condense the energy into a purified liquid for the Bount to drink. They even produce a useful vial in their sacs to store the elixir (which takes the form of a red, glowing, blood-like liquid). After the soul elixir has been ingested, the Bount who took it immediately experiences the effects, with veins popping from their skin. Kariya created the bitto by sacrificing Yoshino Sōma, the only Bount able to reproduce, in an elaborate ritual, producing a large swarm of them.

List of Dolls
Kariya's doll has the ability to manipulate wind. Kariya merged with his doll, allowing him to control it without releasing it into its true form. While in its, true form, Kariya can move the wind at such speeds in order to generate lightning. Messer also gives Kariya the ability to move at high speeds, similar to Flash Step.
 * Jin Kariya - Messer

Dalk is able to manipulate its metallic body to create weaponry. In the Doll's spider form, it can make webs to trap her opponents, making it easier for it to attack, or possibly kill the one fighting the Doll. Its sealed form is a metal sphere.
 * Go Koga - Dalk

Not much is known about Cain's doll, as it barley made an appearance. Cain was a Bount that started off without a Doll (like all the other Bounts,) but once he summoned his Doll, it killed him, because the Doll saw his lack in power. The only ability shown by the Doll, was his larger form. The Doll's larger form looks to be a mantis-like creature.
 * Cain - Waineton

These twin Dolls are the smallest amongst the Bounts, as the Dolls themselves are a bottle cap. Despite both of the Doll's small size, it has great power, as the twin Doll's power is to manipulate water, making its power source nearly unlimited. They can wrap themselves around their opponents in order to drown them, or even flood a person's body, killing them from the inside out
 * Ho and ban - Guhl, Gunther

Utagawa can create snakes from almost anything, by merely hitting Fried against it. Utagawa can also intercept Flash Steps, through a barrier called snake net. Once the technique is activated, if something is seen as a threat to Utagawa through Fried, it will be attacked no matter where the threat runs to by snakes emerging from the ground.
 * Ryo Utagawa - Fried

Ritz is a small little doll, with great power. This doll has the ability to possess her opponent. As shown in Mabashi's battle with Kurodo, Rukia, and Orihime, once Rukia was possessed, she couldn't hear, and had no control over her actions. Mabashi and Ritz also had complete dominance over her abilities.
 * Mabashi - Ritz

Baura has a whale-like appearance. Sawatari sits atop Baura. Baura calls his owner "boss." The Doll's stomach is an alternate dimension, and whomever is eaten by Baura, the person will die if they stay in there for too long, giving Sawatari and Baura power.
 * Sawatari - Baura

Gesell is a huge, eyeless monster. It has the ability to manifest many melee weapons from its limbs.The monster can see through the eyes that generate light, as his master does through his glasses.
 * Ugaki - Gesell

Nieder, unlike the other Dolls, takes on the form of a weapon. In its base form, the fan can fire needle-like projectiles at its target. It can also be used for defense against regular attacks. The jian part of the Doll is used for regular offense. When the fan's size increases, it can protect Yoshi against all attacks, but Yoshi looses all form of offense. When the jian increases in size, it's offensive power increases further, as the jian gains a trail of energy swords.
 * Yoshi - Nieder

Yoshino's doll takes on the form of a humanoid-fire beast, which can generate fire. No matter how many times Goethe is cut, it will always regenerate. If however, it is stabbed through the heart, it will fall to pieces, though all of those pieces are able to attack before Goethe regenerates. Goethe also responds greatly to Yoshino's maternal spirit energy, as he never left Yoshino's side when she was at her weakest. In the end, Yoshino and Goethe merged together, giving Yoshino great power. In the end, they both died together, and gave birth to the bittos.
 * Yoshino Sōma - Goethe