Doll

Dolls 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 fulfill her final wish: for her to be merged with him

Like a zanpakutō, dolls are generally sealed into an object and released as necessary (Koga Gō'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.

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, 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.