Kalil, known as Cleo in Nier Replicant, is a child Shade 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 P-33, 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.
Ultimately Kalil and P-33 died tragically in a battle with Nier and his party - which was motivated by P-33 attempting to protect Kalil from them.