Emeralda Kasim (エメラダ・カーシム, Emerada Kasim) is a nanomachine colony built to aid the human race. Kim Kasim, Fei Fong Wong’s second known incarnation, created Emeralda during the Zeboim era by analyzing Elly’s gene pattern, and created a nanomachine colony. At the time, Miang was manipulating the government, and wanted to reset the human evolutionary cycle by starting a worldwide nuclear war. She also commissioned Kim to advance his work on nanomachines in order to artificially enhance human evolution. Knowing this, Kim removed Emeralda from the main research facility. When Miang found out, she dispatched a special military force to seize Emerelda’s tank. The nanomachines of which Emeralda was composed, stopped, dismantled, and engaged in a pseudo perpetual state. She is a strong character physically, but her child-like knowledge of the world gives her a strong dependence upon Fei, whom she recognizes as Kim. With her elemental Ether abilities and the ability to alter her body's shape, she is readily equipped with devastating attacks. In her adult form, gained by completing the Lighthouse side quest on disc 2, Emeralda's stat gains far exceed those of any other character, with all of her stats increasing upon level-up instead of only some. This distinct combination of good physical skills and ether ability pool on top of making her a great choice for on-foot combat, perhaps not-coincidentally maker her an ideal combination of the best traits of her 'surrogate parents.' Her weight in both child and adult form is 212 pounds, as her artificial body is far heavier than it appears.
Like Seibzehn, Emeralda's Gear, Crescens, was originally scheduled to align with an Anima and become an Omnigear, El Crescens. However, this aspect was removed during the final phases of development, although if one thinks about it, there really would not be a way plot-wise for this to happen, as Emeralda is an artificial construct and thus would not be of much use to Deus on her own, unless one considers how the other party members' Omnigears were reconstructed after their loss of power confronting Deus.
Although her vocabulary is limited, she is able to comprehend most things. In the final cutscene she is seen in her adult form, suggesting that showing up for the Lighthouse side quest is canonical with the story.