Chameleon

"It consumes trion to camouflage your body into the surroundings."

- Kyōsuke Karasuma about Chameleon

Chameleon is a clandestine Optional Trigger that allows the user to become temporarily invisible, consuming trion during use.

Appearance
Chameleon causes the user's body to progressively become transparent until it disappears from sight altogether. The members of Kazama Unit have special devices installed on their uniform that glow with green light when the Trigger is activated.

Overview
Chameleon did not exist two years prior to Yūma Kuga's enlistment in Border. It was created shortly before Kazama Unit began participating in rank battles and enjoyed immediate popularity. However, Shirō Kikuchihara's Side Effect rendered it largely useless, allowing his squad to rise in the rankings and become A-Rank in a short amount of time.

Black Trigger Capture Arc
Kazama uses this to launch sneak attacks at Jin, though the latter's Side Effect makes it ineffective.

Border Enlistment Arc
Kazama uses Chameleon in his solo battle against Osamu. After being defeated by him over 20 times, Osamu discovers the Chameleon's weakness: it cannot be used in conjunction with other Triggers. With this information, Osamu fills the room with bullets, which forces Kazama to not use Chameleon to block against the bullets.

Large-Scale Invasion Arc
Kazama Unit uses this against Enedra, both during the initial and final fights.

B-Rank Rank Battles Arc
Sasamori uses Chameleon to sneak up on Yūma and hold him in place during the Round 2 battle. During the Galopoula Invasion, Kazama uses Chameleon to hide and defeat Ratarikov. The latter managed to deduce its mechanics, however. Wakamura and Miura also use Chameleon during the Round 5 rank battle to sneak to Katori's aid.

Abilities
Chameleon renders the user invisible, allowing them to move in a good position to strike, but also to evade or retreat. The ability to maneuver behind the opponent's back makes it a rather powerful Trigger.

However, Chameleon has a few downsides. The main one is that the user cannot utilize any other Triggers while concealed, which renders them vulnerable to attack and prevents the activation of this Trigger against weapons with a wide area of effect. Furthermore, if the target has fast enough reactions and a general knowledge of the direction a Chameleon user is coming from, they can counter the moment the opponent becomes visible to attack. To avoid this, a Chameleon user can physically restrain the target long enough for an ally to finish them off. Since they are invisible not only to the enemy, but also to their own teammates, Chameleon can generate coordination problems, especially with long-range fighters. It was also implied to be somewhat heavy in terms of trion consumption. The uniforms of the members of Kazama Unit have special devices embedded to decrease it, instead increasing the cost of their trion body.

It should be noted that although this Trigger hides the user from sight, it does not conceal their trion signature, so they still show up on Radar, which reduces its efficacy in rank battles. This weakness can be turned into an advantage by combining Chameleon with Switchbox, as the trion readings created by the latter can be utilized to mimetise that of a Chameleon user. Hound is an excellent counter to Chameleon, since, when set on automatic mode, it is able to detect and attack invisible foes. Trion leaks can also give away the user's location.

Users
See also: Chameleon Users

Chameleon has 11 known users within Border. There used to be more, but the rapid ascent of Kazama Unit and Kikuchihara's Side Effect decreased its popularity. The members of said unit are particularly noteworthy users of this Trigger.