Kalil, known as Cleo in Nier Replicant, is a child Gestalt who, along with his mother, was chased into the Junk Heap by a group of Replicants on a Shade hunt. There, he found and befriended P-33, whom he nicknamed "Beepy".
Kalil is a young Shade and has a straightforward and cute demeanor. He and his mother were chased into the Junk Heap by Replicants. His mother loved him deeply and became a decoy to let him escape, being killed by Replicants in the process. When Kalil was crying and alone, he met a P-33 unit, who decided to become the young Shade's protector. They spent a lot of time together, becoming very close friends, and wanted to explore the world together. Kalil eventually gave a new name to the P-33, Beepy.
Ultimately Kalil died tragically in a battle with Nier and his party—which was motivated by Beepy attempting to protect Kalil from them. After Beepy was severely damaged, Kalil fought the party by himself, with lethal consequences. In his final moments, he apologized to Beepy for being unable to protect him.
Kalil's time with Beepy was short, but it marked the P-33 forever.