Device

Device (デバイス, Debaisu ) are weapons that a Blazer are able to manifest from their souls. At times Devices are referred to as Holy Swords, Demon Bows, Cursed Tools and Blessed Tools.

Summary
Devices are the materialization of a Blazer's soul as a weapon, which can be used in battle. A Device takes on an assortment of different forms and abilities based on the Blazers themselves as shown with Kuraudo's Orochimaru which can extend and move at will. The shapes that a Devie can take on ranges from simple weapons like swords or spears to more modern weapons such as firearms or chainsaws. A Device is able to take form as other types related to the Blazer's abilities like the Brush of Demiurge manifested by Sara Bloodlily whose form is that of a paintbrush and palette.

Being the manifestation of a Blazer's soul, Devices are able to withstand a great deal of damage without bending let alone breaking. However, there are cases when a Device does break, its destruction leads to the Blazer losing consciousness. There are also some Blazers who're able to summon more than one Device or multiple copies of the same Device.

A Device can be deployed in  for practice and/or mock battles, leading to causing damage to a person's stamina instead of actual physical damage. It can also be used if the Blazer doesn't intend to cause real damage to their opponent. Despite a Device not being able to cause damage to an opponent or kill them, attacks that are overwhelming enough can put people in a comatose state.

A Device also serves as a medium for Blazers to utilize their Noble Arts, which is their Trump Card in battles.

There are rare occurrences where a Device and change or evolve because their Device reflects their inner spirit and everything about them. Therefore, if a Blazer completely "rebuilds" themselves, their Device will change as well. This also includes how many of their Devices they can summon and the size of the device. It is first shown with Kuraudo whose Orochimaru turned into two blades instead of one after learning the  Ayatsuji Itto-ryu.

Trivia

 * In the anime, summoning Device's are sometimes made more dramatic. For example, Ikki would "draw" his device as he would for a normal sword from its' scabbard.