Copperhead is a Category IV Kaiju.
Copperhead is a quadrupedal Kaiju with six eyes (three on each side of its face), and a thick, craggy hide hide that resembles cooled magma. The skin of its underbelly and chest are cracked, and underlined with red bioluminescence that resembles lava.
Despite its appearance, Copperhead's blood retains a bioluminescent blue. Copperhead can hear sound from great distances, and is restless in hunting its prey once it begins to target them. Like all Kaiju, Copperhead is vulnerable to Nuclear Weaponry.
Shadow Basin Attack
Five years following Operation Blackout, Copperhead roams the Australian outback. When the Jaeger A.I. Loa activates the hangar doors of Shadow Basin, it sets off the base's alarms and draws the attention of Copperhead who investigates the noise.
Upon arriving to the buried base, Copperhead kills the survivors of Meridian City. Tearing into the base, Copperhead spots Atlas Destroyer and pulls the Mark-3 Jaeger out of its hangar, throwing it over the cliffside the base is situated near.
Leaping down, Copperhead barrels into Atlas Destroyer, throwing the Jaeger off with a tail strike. The tail strike sends the Jaeger tumbling toward the edge of a huge chasm. Copperhead charges Atlas Destroyer, throwing itself toward the Jaeger. Atlas Destroyer is able to drop flat and Copperhead flies over it, barely landing a claw swipe. Copperhead falls over the drop-off, smashing into the canyon wall before falling to the canyon floor.
Meridian City Pursuit
Copperhead is drawn to Meridian City by Atlas Destroyer's alarm system. It's approach is detected by Spyder, who informs the rest of Bogan. Shane allows Taylor Travis and Mei to pilot Atlas Destroyer to safety. Copperhead moves to attack Atlas Destroyer while its still lying on the ground.
While Atlas Destroyer is ordered not to engage Copperhead, Taylor's chooses to fight. Copperhead bests Atlas Destroyer despite the efforts of the pilots, tearing its right arm from its socket. Copperhead follows Atlas Destroyer into the direction of a minefield, undaunted by the first and second wave of remote detonations. The third wave of remote detonations catch Copperhead off-guard and render the Kaiju unconscious.
Showdown in Clayton City
Copperhead finds Atlas Destroyer in Clayton City while wandering the city. It knocks the unoccupied Jaeger over, and spots Taylor, Hayley Travis, and Kaiju Boy returning from Hunter Vertigo. It uses its tail to fling a car at the fleeing humans before attacking Taylor, who tries to draw it away from his unconscious sister. The boy transforms into a Kaiju and attacks Copperhead. Kaiju Boy leaps onto Copperhead's back in an attempt to overpower Copperhead, but is thrown off. Copperhead slams its head into Kaiju Boy, knocking him away and pinning him under debris.
Copperhead engages Atlas Destroyer, who pierces and tears away its skin using its Saber Chain. As Copperhead recovers, Atlas Destroyer uses the Saber Chain again, cutting Copperhead's front left leg off with its serrated edges. Copperhead knocks the Jaeger away and tries to tear its arm off a second time. During the fight, Hayley manages to unjam Hunter Vertigo's final nuclear missile. Atlas Destroyer kicks Copperhead into the missile's line of fire, and the Kaiju is killed by the subsequent explosion.