Jammer is a female corporal in the ISA. Like all the troops stranded on Helghan, she participated in Operation Archangel and was marooned on Helghan following Helghast counter-attack that devastated the invasion fleet.
On the day of the evacuation, Jammer and her platoon were pinned down by the Helghast. Unfortunately, the Intruders Captain Jason Narville had sent to evacuate her platoon were destroyed and he couldn't spare anyone else. Rico went to aid them instead, but by the time they fought their way out and were spotted by Narville and Sev, the remaining ISA Cruisers were shot down by MAWLR fire.
During the six months marooned on Helghan, Rico had formed the Raiders and Jammer was second-in-command. When it had been discovered that Narville and Tomas Sevchenko had been captured by Jorhan Stahl's private army, the Raiders launched a daring assault and rescued Sev but lost Narville's dropship. This then unfolds into a prolonged assault on numerous defense platforms. After successfully clearing the path.
Rico orders Jammer and the rest of the Raiders back to base while he and Sev infiltrate Stahl's base. After Narville was saved, Jammer and the Raiders arrived at Stahl's base, clearly disobeying Rico's orders but Rico himself didn't mind it at all as they needed evac anyway. Jammer is then ordered to take Narville and the other freed POWs back to base to prepare and set out to chase after Stahl, who was planning on using experimental weapons to destroy Earth.
Jammer and all of the rest of the stranded ISA arrive to the space elevator, leading to the space station where Stahl and Admiral Orlock's forces were meeting.
More to be Added
Jammer is an attractive young woman of Hispanic heritage and is always seen with a hood over her head and eye black. She is relatively laid-back, easy-going, and is hardly ever seen stressed. She respects Rico's leadership, but like Rico, she would wave off "bullshit orders" from time to time, something she states that Rico himself taught. She has been credited and self-regarded as crazy, one such occasion being when she was forced to drive through the dangerous apparatus of a garbage shredder in a hasty rescue save Sev and Rico from being killed by it.
She appears to possess some technical skill, including knowledge of Helghast mechanical and computer systems, also like Luger, Jammer shows impressive skills in both hand to hand and ranged combat, though she can be overwhelmed, like at the end of Killzone 3 on the Space Station, she requires the help from Hooper to subdue the Helghast guarding the keycard. She's an excellent fighter pilot, using both an ISA Intruder and a Helghast Strike Ship extremely well. However, she can get a bit reckless, like as when she tries to land her Intruder to pick up Sev and Rico, but constantly dodges RPG fire in the process.
- She is the fifth woman to appear in the series (after General Vaughton's communication officer, Luger, Evelyn Batton, and Hera Visari), and the third woman to actively take part in battles. She is the first woman in the series to be a grunt soldier rather than a higher ranking individual.
- She was modelled after actor/model Eva Mendes.
- Considering that she serves in the military, realistically she wouldn't be allowed to have hair as long as she has and/or have it let down. Due to it obstructing head equipment like helmets and gasmasks.
- It's possible (though uncertain) that Jammer and Rico have some feelings for each other. In the six months they were forced to work together to survive, they seemed to have grown a relationship similar to Rico and Sev's. Jammer is the only person besides Sev whom Rico trusts enough to be his second-in-command.
- In the novel Killzone: Ascendancy, Sev admired Jammer's beauty in several occasions and at the end of the novel he said he's going to buy her a drink and maybe a burger.
- Jammer is one of the icons from the KIllzone trilogy in PlayStation All-Stars Battle Royale.
- In Killzone: Shadow Fall, in multiplayer, there is an accolade of Jammer, entitling her as "The Coporal".