Dolls are Bounts' power given a physical form and act as their weapons.
A Doll is quite similar to a Shinigami's Zanpakuto, except in how they function and the fact the Doll's personality is always dominant. After they are released, they function on their own but can easily be sealed again and the Bount's level of control over the Doll depends on the controller's power and relationship with it. If the Doll or the Bount are badly hurt in a battle, depending on the level of damage, it is possible for the Bount to lose control of their Doll, causing it to either reseal itself or fly into a rage and kill their owner. A Bount may also be killed by a Doll if they aren't strong enough to control it, but if they have an actual relationship with the Doll that goes beyond that of master and servant, this can be overcome. Dolls are usually sealed into the form of an object until the Bount controlling them needs them, again similar to a Zanpakuto. The object varies greatly, often a reference to the Doll's powers, and they are released by the command, "Zeige Dich" then saying the Doll's name. To summon their Doll into existence, a Bount undergoes a ritual and the instructions on how to do so was given to Jin Kariya by Ran'Tao. The ritual requires the ingredients of the human body, sulfur, phosphorous, carbon, water, fat, magnesium, and lime. When a Doll is first summoned, it is relatively small in size and power, but both grow as the Bount becomes stronger. Also if a Doll is killed, the Bount owner dies as well and vice versa.
The Bitto are a unique mosquito-like type of Doll created by a special process that sacrificed Yoshino Soma in an intricate ritual thought of by Jin Kariya and Ugaki. They drain the souls from humans, converting it into a purified liquid that the Bounts can drink, which they store in sacs on their body that can be easily removed. When a Bount drinks the liquid, it causes a dramatic increase in power greater than what they would gain by feeding on the souls themselves.
Goethe is Yoshino Soma's Doll and takes the form of a humanoid fire being, possessing the power to unleash fire attacks and regenerate from injuries. But if pierced through the heart, Goethe will fall to pieces, though he can still attack before he regenerates. He is very close to Yoshino due to her maternal spirit energy and eventually merged with her. When sealed, Goethe takes the form of a bracelet and claw on Yoshino's finger.
Fried is Ryō Utagawa's Doll and takes the form of a large gold snake, possessing the power to turn objects she strikes into snakes. She can be wielded as a whip, but can shape herself into a blade or a shield and her most powerful ability is her Snake Net technique. Once activated, Fried can unleash pillars of snakes wherever the opponent steps, leaving them no room to attack. When sealed, she takes the form of a gold pocket watch.
Guhl and Gunther
Guhl and Gunther are Hō and Ban's Dolls and are the smallest, taking the form of a pair of bottle caps. They possess the power to manipulate water and can wrap around an enemy to drown them or even force their way into an opponent's body to take them down from the inside out.
Dalk is Gō Koga's Doll and first took the form of a slender woman like metal being, but later obtained a more spider-based form. She can manipulate her metal body to form weaponry and use other attacks and after gaining her spider form, she could create metal webs. When sealed, Dalk takes the form of a metal sphere.
Gesell is Ugaki's Doll and takes the form of a swarm of eye-like creatures, but its true form is that of an enormous eye-less monster. Its is able to appear out of the shadows and form its limbs into various melee weapons, making it an excellent stealth attacker. Gesell is sealed within a deck of cards that Ugaki uses to give it commands.
Nieder is Yoshi's Doll and unlike other Dolls, takes the form of a weapon, a fan that can fire needle-like projectiles and be used for defense, chained to a jian, which can be used for offense. She can form the fan into a more armored form, making it larger and able to block all attacks, but Nieder loses its offensive capabilities. Yoshi can do the same with the jian, making it able unleash a trail of energy swords. When sealed, Nieder takes the form of an object resembling a closed fan.
Baura is Sawatari's Doll and takes the form of a large whale-like creature with a chair-like protrusion on top for Sawatari to sit on. He can manipulate space to disappear and reappear and his stomach is an alternate dimension. When Baura swallows someone, they are imprisoned in that dimension and if they are there too long, they will die, leaving the soul for Sawatari to absorb. The Doll can also expel anything he swallows, such as debris and energy attacks.
Waineton was a Doll summoned by a young Bount named Cain under Koga's care, who summoned his Doll too early. Very little is known about this Doll since almost immediately after it was summoned, it transformed and killed Cain since he wasn't strong enough to control it.
Ritz is Mabashi's Doll and takes the form of a small flower like creature, possessing the power to possess people. Once she has done so, the possessed person cannot hear or control any of their actions and Ritz can make them use any of their powers. She can also move at high speeds and tunnel through the ground, allowing her to quickly and suddenly use her possession ability. When sealed, Ritz takes the form of a seed.
Messer is Jin Kariya's Doll, possessing the power to manipulate wind but unlike other Bounts, Kariya can use its powers without releasing its true form since he is merged with it. It allows him to move at high speeds and execute wind attacks and when it is released, Messer takes the form of a pata sword with a wind blade. It can also create friction in the air to generate lightning and when unreleased, it is sealed into Kariya's body.