Yūma's Black Trigger

"Its ability is to learn other abilities and make them its own."

- Shūji Miwa describing the effects of Yūma's Trigger.

Yūma's Black Trigger was created by his father Yūgo Kuga to prevent Yūma's death. Since neither Yūma nor Replica gave it a name, they refer to it simply as Dad's Trigger or Yūgo's Black Trigger.

Appearance
The Trigger Holder takes the form of a black-colored ring with a thin white line running through its sides, forming two small circles which are parallel to each other. When activated, this Trigger summons a black-colored jumpsuit armor with thin red lines running through it, and it covers most of the user's body with the exception of their head.

Background
When Yūma still lived in the Neighbor world, he and his father, Yūgo, participated in the Neighbor Wars. During one of the battles, Yūgo told Yūma not to participate in this battle, because earlier that day they had found the dead bodies of some of their men, and they were some of the most powerful of their side. Yūgo suspected it was the result of the other side having a Black Trigger. Yūma, however, just pouted and didn't really think much of his father's words. After his father had left to go fight, Yūma left their side's fortress and went outside into the battlefield. Seeing multiple battles he could help win, he decided to make stealth attacks eliminate some of the enemy units. But during his exploring, he ran into an unknown enemy, and wasn't strong enough to defend himself, resulting in his near-death. Yūgo, finding Yūma's wrecked body, created a Black Trigger, a ring. He then sealed the body of the dying Yūma inside the trigger, substituting it with a body made of trion (with which his hair is white); thus saving Yūma. However, this took all of Yūgo's power, and so he turned to dust, crumbled and died. Replica theorizes Yūma's body, although sealed, is still degrading, and Yūma will eventually die.

Abilities
The power Yūma's Black Trigger is such that, coupled with Yūma's exceptional fighting skills, it allowed him to incapacitate two A-Rank Border agents while attempting to neutralize them peacefully, and even to defeat the mighty Organon user Viza. Its primary asset in combat is an arsenal of versatile seals that create different effects, which can be also amplified or combined and disappear after one activation. It also bestowed on Yūma his father's paranormal capacity to detect lies. The black garment it creates seems to offer some degree of protection, since Yūma took no damage from Chano's Asteroid. However, the armor can be easily penetrated by stronger attacks, such as the bullet of an Eaglet and Organon's blades.

Aside from the seals, Yūma's Black Trigger has a series of abilities that are unique even among Black Triggers. Most remarkable is the one associated with the purpose of its creation, the permanent substitution of Yūma's fatally wounded flesh and blood body with one made out of trion in order to slow down his death to a near halt, meaning some functions of the Trigger are constantly active. The trion body itself has three main peculiarities. The first is its ability to repair itself almost instantly when damaged, which no other trion body possesses; however, this comes at the expense of its durability, as a car crash is enough to crack it. A second distinctive feature is that Yūma's trion regenerates itself despite him being always in a trion body. Lastly, this special trion body allows Yūma to activate other Triggers normally, causing it to be swapped with an ordinary combat body generated by the Trigger Holder in use.

As a side effect, Yūma no longer needs to sleep and has greatly enhanced physical abilities even outside of his combat trion body. This uniqueness has proven to be an instrumental asset in battle that allowed Yūma to surprise and beat Viza. Viza's defeat was made possible by another singular ability of Yūma's Black Trigger, which is the capacity to use its seals even without activating it properly and creating a combat body. The same applies to multiplier and compound seals. They can be used even when Yūma is in a trion body created by another Trigger.

Yet another singular characteristic of Yūma's Black Trigger is that its seals can also be used independently by Replica, a Trion Warrior, and its small avatars. Replica is also capable of fusing with Yūma's combat body. Indeed, Yūma's Black Trigger peculiarly relies on Replica to bring out its full potential: in fact, it is the Trion Warrior who is generally in charge of creating multiplier and compound seals, which it can do also through its small avatars, although this way the process will take longer. A similar drawback applies if Yūma sets the seals on his own. Furthermore, although Yūma himself can add new seals by analyzing other Triggers, he is unable to do so on the spot, and thus relies on Replica's help. These seals exceed in power the Triggers from which they are derived. This is linked to the Black Trigger's final ability: the capacity to accrue seals so that, once memorized, they can be accessed during future activations of the Trigger. As a consequence, the scope of its abilities can widen over time if the user has access to other Triggers. The exact conditions that must be met for them to be copied are currently unknown, although two are certainly the exposition to the Trigger in question and the proximity as well as the length of time required by Replica to analyze it.

Seals and Multipliers

 * Bound (「弾」印 (バウンド)): A blue seal with the kanji for "repel" (弾) appears, creating a larger seal in a point within the user's vicinity which can send people and objects flying at incredible speed by repelling them. A person of flesh and blood would die either from the acceleration or from reaching the other end, but trion bodies are not subjected to any risks. Used on objects, it can propel them as projectiles. This seal has a much greater power output than Grasshopper, but only one platform can be created per activation. Multiplier seals catapult the user further. It was first seen in Chapter 1 (Episode 1 in the anime) when Yūma used it to kick a Bamster in the danger zone.
 * Bound Double (「弾」印二重 (バウンドダブル)): This multiplier seal allows the user to jump higher, easily surpassing tall buildings, and to cover greater distances with a single leap.
 * Bound Sexta (「弾」印六重 (バウンドセクスタ)): A multiplier seal that allows the user to reach astounding levels of speed. Yūma used it to rush at Viza and kick him, throwing him off balance and shattering the ground underneath and around them with the sheer force of the impact even though the attack was blocked.


 * Boost (「強」印 (ブースト)): An orange or blue seal with the kanji for "strength" (強) appears on the user's hand, creating a larger seal in the proximity of the chosen target. It is a simple but versatile seal that amplifies the effects of trion, the user's or another person's, increasing the power of an attack or the physical strength of the target if used directly on a trion body. In the latter case, the seal appears behind the target's back, and it gives them enough strength to burst through a pile of rocks. It was first seen in Chapter 1 (Episode 1 in the anime) when Yūma used Boost Double to destroy a Bamster in the danger zone.
 * Boost Double (「強」印二重 (ブーストダブル)): A multiplier seal that enhances the target's strength even further, allowing them to single-handedly lifts that not even a trion body could otherwise manage to move. It gave Yūma enough power to destroy a Bamster with a single punch, as well as to shatter a large portion of the ground with a stomp, raising a curtain of dust to block the enemy's vision. Combined with Chain, it can be used to forcefully control the position of the opponent.
 * Boost Quinti (「強」印五重 (ブーストクインティ)): With this multiplier seal, Yūma was able to create deep cracks in the armor of a Rabbit and to send it flying with a kick.
 * Boost Septa (「強」印七重 (ブーストセプタ)): A multiplier seal that gives the user a gargantuan amount of strength. It enabled Yūma to effortlessly drag an Ilgar down from the sky and throw it into the river below with a single motion.


 * Shield (「盾」印 (シールド)): A green seal with the kanji for "shield" (盾) appears, creating a circular barrier that deflects attacks. Its durability increases if it remains fixed in place, decreases if it is moved. A handheld shield can resist Asteroid bullets without cracking, but a single Kogetsu slash is enough to break it. Furthermore, it can be penetrated by Triggers which have no attacking power such as Lead Bullet. A way to enhance its defensive abilities is to combine it with Boost. Multipliers increase its surface area. It was first seen in Chapter 4 (Episode 3 in the anime) when Yūma used Shield Double to defend Osamu from a Mole Mod.
 * Shield Double (「盾」印二重 (シールドダブル)): This multiplier more than doubles the surface area of the shield. Four simultaneous attacks from a Mole Mod could not put a scratch on it, and, when used by Replica, neither could a beam fired at point-blank range by a Lamvanein-Type Rabbit.


 * Chain (「鎖」印 (チェイン)): An ocher seal with the kanji for "chain" (鎖) appears. A chain emerges from it, which can be used to capture the target. The chains of two or more seals can be connected once summoned, and one seal can attract the chains of all the others. This seal can be placed on a target through physical contact or close proximity. Chain seals can also be activated remotely, which makes them an effective trap when placed on the ground or other surface. They can also contract, restraining the target with debris if placed on any such material. Multipliers increase the range and durability of a chain. It was first seen in Chapter 9 (Episode 5 in the anime) when Yūma used Chain Triple to bind the Ilgar Kitora was battling.
 * Chain Triple (「鎖」印三重 (チェイントリプル)): A multiplier seal that increases the length and thickness of the chain, so that two of them can reach an airborne Ilgar and resist the force generated by Boost Septa without snapping.


 * Anchor (「錨」印 (アンカー)): A blue seal with the kanji for "anchor/grapnel" (錨) appears, creating weights of about 200kg each which can be used to limit the target's mobility. An Anchor seal can be placed through direct contact with the opponent, even if it is the latter who initiates it, for example by attacking the user. Weights can also be placed through interaction with an extension of the Black Trigger, such as the chains generated by the Chain seal, meaning that as soon as the targets frees themselves from the chains, they will be affected by the Anchor seal. It is known to be very trion-consuming. This seal was replicated from Shūji Miwa's Lead Bullet. It was first seen in Chapter 16 (Episode 8 in the anime) when Yūma used it in conjunction with Bolt Quadra to immobilize Miwa and Yoneya.


 * Bolt (「射」印 (ボルト)): An orange seal with the kanji for "archery/shoot" (射) appears. It is capable of a ranged attack by shooting trion bullets. It is possible to place multiple seals and activate them remotely, attacking the target from multiple directions at the same time. Used in conjunction with other seals, it can apply that seal's effect to a distant target. Multipliers increase the number or range of the bullets. This seal was replicated from Shūji Miwa's Asteroid. It was first seen in Chapter 16 (Episode 8 in the anime) when Yūma used it in conjunction with Anchor to immobilize Miwa and Yoneya.
 * Bolt Quadra (「射」印四重 (ボルトクアドラ)): This multiplier seal increases the number and the spread of bullets, making it possible to hit two targets at once. It is often used in conjunction with Anchor in a compound seal.
 * Bolt Quinti (「射」印五重 (ブーストクインティ)): A multiplier seal which can increase the range of the bullets dramatically, allowing Yūma to hit a target several hundreds of meters away. It has been used in conjunction with Boost in a compound seal.


 * Gate (「門」印 (ゲート)): A blue seal with the kanji for "gate" (門) appears, generating a Gate from which a previously analyzed Trion Warrior emerges. When used by Replica, it summoned a black Rabbit of immense power, which had access to the Boost, Shield and Bolt seals, outperforming Aftokrator's own Rabbits. It was first seen in Chapter 69 (Episode 31 in the anime) when Replica used it to protect Osamu.


 * Echo (「響」印 (エコー)): A blue seal with the kanji for "sound" (響) which emits a faint wave of trion through which the user become aware of the morphology of the terrain, the presence of living beings, and the position, distance and conditions of trion constructs, in a way that is reminiscent of echolocation. It was first seen in Chapter 77 (Episode 34 in the anime) in Yūma's battle against Viza.

Compound Seals

 * Anchor + Bolt Quadra (「錨」印+「射」印四重 (アンカープラスボルトクアドラ)): The user combines an Anchor seal with Bolt Quadra, shooting several bullets that generate weights upon contact, making the target unable to move. Thanks to the increase in the number of bullets and the width of the area of effect granted by the multiplier, this technique can affect multiple targets at once.
 * Bolt + Boost (「射」印+「強」印 (ボルトプラスブースト)): The user combines a Bolt and a Boost seals, firing bullets of higher caliber and greater destructive power than the standard.
 * Boost + Bolt Quinti (「強」印+「射」印五重 (ブーストプラスボルトクインティ)): The user combines a Boost seal with Bolt Quinte Of only a few bullets are fired, they acquire immense range and power. When Yūma used this technique, it allowed him to severely injure Hairein from a distance of hundreds of meters, effortlessly penetrating his armored cloak.

Users
The only known users of this Trigger are Yūma Kuga and Replica (seemingly through Yūma). In fact, Yūma is dependent on it to live, and should it be taken away from him, he will lose his trion supply and eventually run out of it, falling into a sort of "sleep mode" unless he can find another supply. However, without his ring, he will be unable to send nutrients to his flesh and blood body, which could lead to his demise. Similarly, Replica receives its trion from the ring. Trion Warriors generated through the Gate seal can also use some of its abilities.

Trivia

 * As noted above, this Trigger has multiple unique traits. It is the only known Trigger:
 * which can be utilized by two users at the same time;
 * that can be used by a Trion Warrior;
 * generating a trion body to be partially active at all times, and the sole to have multiple "layers" of activation;
 * to create two different trion bodies;
 * to rely on external sources for some of its abilities;
 * that can increase its power through repeated uses, as it can create new seals and memorize them;
 * to substantially affect a flesh and blood body;
 * which can create Trion Warriors (excluding Triggers from the filler arc);
 * to have an effect without an user (Yūma was on the verge of death when it was created and his father had just died, so neither of them could have activated it to seal Yūma's body);
 * to alter the appearance of the user without their consent (Yūma's hair turned white);
 * to bestow a Side Effect on someone who did not possess it beforehand.
 * Boost Double is the seal that has been used with the most frequently.
 * Multiplier seals are named after English multipliers (2 and 3) and Latin ordinal number prefixes (4, 5, 6 and 7), albeit loosely in the latter case.
 * Septa (7) is the highest multiplier seen thus far.
 * Many of the seals are similar to Border Triggers:
 * Bound resembles Grasshopper;
 * Shield resembles Border's own Shield, including the fact both are more durable when fixed in place;
 * Chain vaguely resembles Spider;
 * Anchor was copied from Lead Bullet;
 * Bolt was copied from Asteroid;
 * Echo resembles Radar.