Shimkif, an Agbui operative serving the Grysk Hegemony, accompanied Haplif on a clandestine mission to infiltrate the Chiss Ascendancy. She was the mother of Frosif and played the role of Haplif's wife. During the plot to destroy the Chiss Ascendancy, Shimkif's duty was to maintain order among the Agbui crew and manage their starship.
Alongside her daughter, Frosif, Shimkif joined an Agbui endeavor aimed at instigating a civil conflict within the Chiss Ascendancy. This operation was under the direction of Haplif, another Agbui, and the Agbui were under the command of the Grysk agent Jixtus. Throughout this mission, Haplif intended to influence a young Chiss couple, Yoponek and Yomie, to aid his infiltration of the Chiss elite. Yoponek informed the Agbui about an ambitious Xodlak Councilor on the Chiss planet Celwis, named Xodlak'uvi'vil (Lakuviv). Haplif wanted to exploit Lakuviv in his attempt to spark a Chiss civil war. Haplif attempted to persuade Yoponek to travel to Celwis to introduce the Agbui to Lakuviv, but Yomie refused, preferring to witness the month-long Grand Migration on the Chiss world of Shihon. Yoponek, while intrigued by Haplif's proposition to meet a significant historical figure before his rise to power, leaned towards Yomie's wishes. Given the strict schedule imposed by Jixtus, the Agbui couldn't afford to delay their visit to Celwis by an extra month. Consequently, Haplif and Shimkif decided that Yomie needed to be dealt with. They attempted to stage a fake marriage ceremony between them in an effort to sway Yomie's decision and convince her to go to Celwis. However, this ceremony failed, and the Agbui proceeded to Shihon. En route, Shimkif learned that Jixtus was awaiting them at Shihon, and she instructed Haplif to prepare his documents.
Once on Shihon, Shimkif dedicated herself to disrupting the Grand Migration. In the preceding days, she studied the migration patterns and devised a strategy to interfere with them. Over three days, she poisoned certain migration areas and strategically placed extra food in others. She captured some birds and directed them to the areas with abundant food. Eventually, the birds discovered the new food sources, which ultimately disrupted the migration's equilibrium, causing it to end prematurely. Satisfied, Shimkif returned to the Agbui ship, only to be informed by Haplif that Yomie was determined to witness another migration on Shihon. Frustrated, Shimkif pointed out the difficulty of disrupting another migration without prior planning, but they agreed to find an alternative way to thwart Yomie's plans. At the Panopyl Mountains migration, Shimkif once again left the Agbui ship to sabotage the migration. However, this time, her efforts were unsuccessful. Instead, she poisoned Yomie with the venom of a greenstripe. Later, when Haplif attempted to persuade Yomie to go to Celwis, she tricked him into revealing the Agbui's telepathic abilities. Threatened with exposure to Yoponek, Haplif was compelled to kill Yomie, and the Agbui disposed of her body during their journey to Celwis.
Arriving on Celwis, the Agbui took residence on the ranch of Xodlak yubal rancher, Xodlak'phr'ooa (Lakphro). One day, Frosif was triggered by Lakphro's daughter, Lakris, when she used a brass sealer to compel a growzer to approach her. Lakphro immediately went to Frosif to check on her well-being. Frosif attempted to telepathically connect with Lakphro, but the rancher resisted. Aboard the Agbui's ship, Frosif informed Shimkif and Haplif about the incident. Haplif grew frustrated at his inability to telepathically read Lakphro, so he and Shimkif decided to try to manipulate him by giving his wife, Lakansu, and Lakris a pair of their nyix brooches as an apology. A week later, Shimkif, along with Frosif and Haplif, gifted Lakansu and Lakris these brooches, and the Chiss accepted the gesture.
As they departed Celwis, Shimkif witnessed Lakphro and Haplif engaged in combat. Recognizing that Haplif was unlikely to survive, Shimkif instructed the Agbui to abandon him.