Teigu

Teigu (帝具, lit. "Imperial Arms") are mysterious and extremely powerful relics that exist in the world of Akame Ga Kill! They are rare, and only the strongest of warriors are able to wield them. Some have the appearance of equipment or weapons, while others seem to be living creatures. It is implied that a form of magic was used to create them.

Origin
The Teigu were created on the instruction of the First Emperor, who feared that the Empire he had founded would eventually fall. To prevent this, he gathered many materials and hired many scientists throughout the world to make strong weapons and defenses. The creation of the Teigu are the result of their efforts. There were 48 Teigu in all, but almost half of them were lost during a civil war about five centuries before the start of the story. Several Teigu have been seen to be destroyed; it is not known how many of the original 48 remain.

Many Teigu were created from the remains of Danger Beasts that had unique powers, imbuing the equipment with special abilities. Many weapon and armor type Teigu were forged from a rare metal called Orichalcum. Teigu are not limited to one ability; some are known to have secret powers that are yet to be discovered, and some have powers that are lost to history.

Creation
Teigu were presumably created through a long and intricate process. As stated by the Strange Elder, the weapons forged into Teigu must have a Danger Beast's attributes imbued into it, and the raw materials selection can determine the strength and its capability.

The First Emperor who spearheaded the project, called forth and hired various artisans, engineers, scientist, alchemists and even mystics in creating the 47 Teigu's and as such each weapon was presumably uniquely constructed in its own unique process due to the sheer number of creators gathered by the Emperor, who also commissioned and tasked his imperial armies with the task of locating and acquiring several rare materials for the weapon's creations. Having successfully had them obtain the hides and corpses of Super and Special class Danger Beasts such as the dragon Tyrant and The Rare alchemical super steel, Orichalcum.

During this time, the first emperor had also successfully procured the services of the famous smiths of the Wakoku Nation, who thus then used their legendary techniques and immense smithing technology to create the One Hit Kill Sword; Murasame.

Another team of engineers where then able to supposedly create the Teigu, Shambhala by somehow obtaining and learning the mystics of a now lost nation to manipulate and control space; an art they then used to create the Imperial Arm.

Although unconfirmed, it was stated and implied that a type of magic was used in the Teigu's construction.

Usage and Limitations
While the Teigu give its users amazing powers, they are not almighty. It is stated that there is no Teigu that can resurrect the dead. Even if a user is strong enough to use a Teigu, it can still reject them, and a user's first impression of it affects their compatibility. The user must be compatible with the Teigu in order to wield it.

Biological Teigu are shown to be capable of regenerating after serious damage, but are not indestructible; if their core is destroyed then so is the Teigu itself. Some Teigu have limitations in its usages. Overusing a Teigu has had a variety of consequences. For example, Pumpkin was excessively overheated beyond its limits. Despite this, Mine still used it for one last grand attack, leading to its own self-destruction as a result. Certain Teigu begin to fuse with the user if it is overused, slowly transforming the user into the original Danger Beasts. This has been shown through Tatsumi and Leone.

Several Teigu were shown to have a hidden ability (奥の手, oku no te, lit. secret move), often referred to as "Trump Card" or "Ace in the Hole". It is said that not all Teigu have those, however, certain users can develop such abilities themselves. Usually, such moves are the most powerful, last resort ones.

If two Teigu users engage in a battle, both with killing intent, one of them is certain to die. If multiple users are involved, there is a high probability of only one of them surviving.

An ironclad rule among its users is that every person can wield only one Teigu, since a single Teigu requires a considerable amount of mental and physical strength in order to be controlled. According to Esdeath, if one were to use two Teigu at the same time, they would be destroyed by it. However, it is not outside the realm of possibilities to utilize two Teigu at once, should the user be compatible with both Teigu and have the physical strength to withstand the burden.

Currently, Wave has been the only one that has ever been able to use two Teigus at once. However, despite the minimal time spent using two Teigu, Wave suffered severe damage to his body, stating that an unspecified organ was damaged beyond repair and required that he see a doctor once a year.

Teigu can also be self-destructed, either through detonation or overuse shown when Bols self-destruct Rubicante and Mine's Pumpkin was destroyed because of the Teigu is unable to withstand the overheat.

Known Teigu
Out of the original forty eight Teigu created by the First Emperor, only thirty-six have been shown so far, out of which fifteen have been destroyed, while two are currently missing.

Teigu Тейгу Armes Impériales 帝具

Trivia

 * Another Emperor 400 years prior to the present of the Story had also attempted to create his own Teigu and try and create weapons that surpasses the original 47 using his own resources. However this venture ended in failure, due to the fact that despite being powerful in their own right, the newly created weapons where nowhere near as powerful as the Teigu and were thus then named Shingu.
 * In the island continent of Wakoku, the creation of Teigu like weapon is universal knowledge among the 22 nations of the continent and are instead referred to as Meihou. That unlike the Empire, can be easily mass produced with the right materials and if the needed money for production is meet.