Leatherback is a Category IV Kaiju.
Leatherback is a naturally hostile creature whose appearance is akin to that of a gorilla; however, if injured, Leatherback uses hit and run tactics to defeat foes. It will retreat from battle and hide until the enemy is distracted. Pouncing on enemies from behind, Leatherback uses the weight of its opponent against them.
Leatherback's fists are like maces, the hard protrusions that cover them can tear through armor. Its thick skin allows it to withstand great amounts of damage without faltering. This is further enhanced by bony armor on the shoulders, as well as a crest-like plate that covers the top of its head. It possesses fourteen bioluminescent tendrils on the back of its head that wiggle as a sign of agitation.
Of the two, Leatherback does not possess the same level of intelligence or cunning as Otachi. Its strength lies in its rage, particularly when challenged in an attack. Its movement resembles that of a gorilla, walking on the knuckles of it's large, shovel-like hands, or making great leaps. Leatherback has six visible eyes. The Kaiju's most deadly trait is a large, four-lobed organ on its back that can naturally charge and generate an electromagnetic pulse which disables all electronics in a wide surrounding area, a dangerous threat to digitized Jaegers.
Leatherback emerges to hunt down Newton Geiszler in Hong Kong, along with Otachi. Crimson Typhoon, Cherno Alpha, and Striker Eureka are deployed to fight them. Otachi single-handedly engages Crimson Typhoon and Cherno Alpha while Striker Eureka--ordered to stand fast--watches on. Despite the two-to-one disadvantage, Otachi manages to shut down Crimson Typhoon and seriously wound Cherno Alpha with her acid, melting the heavy armor on its head and chest.
Leatherback takes advantage of the situation and decides to attack Cherno from behind. Striker tries to run to Cherno's aid, but before it can get there, the two Kaiju critically damage Cherno. Otachi rips off one of Cherno's arms and proceeds to intercept Striker Eureka, leaving Cherno Alpha defenseless as Leatherback rips the Jaeger apart, drags it underwater, and crushes the cockpit, killing both of its pilots.
Afterward, while Striker is distracted with giving Otachi a beating and being moments away from killing her with its chest missiles, Leatherback charges its organic EMP and fires it, disabling the Jaeger. Leatherback goes up to the powerless Jaeger and prowls around it as its pilots, Rangers Hercules and Chuck Hansen emerge from its Conn-Pod. Knowing their chances of survival are virtually nil, the Hansens do the only thing they can: they aim flare guns at the beast’s face and fire.
The flares hit home and burn one of Leatherback's eyes. However, as expected, they merely stir Leatherback to anger. It raises its fists to smash the Rangers, but then it hears the noise of helicopters approaching. The helicopters bear Gipsy Danger, which, being an analog Jaeger, survived Leatherback’s EMP pulse with its systems intact.
Gipsy’s pilots, Rangers Raleigh Becket and Mako Mori, release the Jaeger, which lands and stands ready. Leatherback charges, but Gipsy sidesteps, seizes the EMP-emitting organ on the Kaiju’s back, rips it off and tosses it away. Furious, Leatherback grabs Gipsy in a bearhug, spins it and throws it. Gipsy goes flying onto a port, destroying an overpass and a great many containers as it lands and rolls. But the Rangers bring the roll under control; Gipsy finishes it crouched and ready.
Leatherback climbs onto the dock. With enraged screams, it charges Gipsy. The Jaeger runs straight at the charging Kaiju and, using its dorsal thrusters, leaps into the air and lands with its fist slamming hard onto Leatherback’s head. It grabs the disoriented Kaiju’s head and delivers two more punches before delivering a third blow.
The force of this third punch is hugely increased by the firing of thrusters in the Jaeger’s elbow. Referred to as the elbow rocket, the thrusters drive Gipsy’s fist in a massive blow straight into Leatherback’s face, knocking it down. Pained and disoriented, Leatherback finds a stationary crane, picks it up by the jib, and hits Gipsy twice with it, doing minimal damage but the blow knocks Gipsy back briefly.
Gipsy grabs five shipping containers, two in one hand and three in the other. It smashes Leatherback across the face with one set, then slams both sets into the sides of Leatherback’s head. It finishes with a another blow to Leatherback’s face, knocking it down. Again hurting and disoriented, Leatherback is unable to stop Gipsy from grabbing it from behind, locking its arms under the Kaiju’s shoulders. Gipsy lifts Leatherback clear off its feet and throws it.
Infuriated, the Kaiju slams both fists into the ground before charging at Gipsy. The two grapple, with Leatherback using its enormous strength to force Gipsy backward toward the edge of the dock. Gipsy frees its right arm, activates its plasma caster and begins firing repeatedly into Leatherback’s chest, severing the Kaiju’s left arm and causing massive internal damage to the Kaiju’s thorax. The Rangers empty the entire clip into the Kaiju’s chest. It dies just as the back of Gipsy’s feet almost reach the edge of the dock, its chest a glowing blue mess because of its spilled blood. Gipsy pushes the carcass away and it falls on its back.
But then Raleigh recalls the last time he thought a Kaiju dead after hitting it with multiple plasma caster blasts. That time, the Kaiju Knifehead had played possum and then viciously attacked, with horrific consequences. He and Mako make sure Leatherback is truly dead by firing another volley from the plasma caster in its left hand into the Kaiju’s chest, burning it, causing a small combustion, and causing damage beyond any possibility of survival.
- Leatherback is the only Kaiju to use improvised weapons in Pacific Rim.
- Leatherback is a playable Kaiju in Pacific Rim: The Video Game.
- NECA'S Pacific Rim second action figure series featured a Leatherback figure, released September 2013.
- Leatherback is similar to the Japanese King Kong who could attack with an electric grasp.
- The name "Leatherback" is a play on the name of adult male Gorillas, the silverback. Leatherback's body language is similar to that of Gorilla's in the way it moves on its knuckles and charges at its enemies.
- Leatherback is also the name of a sea turtle species, the Leatherback sea turtle.
- Some of Leatherback's features (the tentacles from the back of the head, and a exposed vertebral column) are similar to Sammael, a demon from del Toro's Hellboy.