Immanuel, a special unit machine, known as the forest king to residing machines, is a remainder of the founder and previous leader for the machines of the forest. After their founder died, the machines who reside there as part of the forest kingdom, made a commitment to protecting their young king until the day he grows up to become their leader. It is learned that after many years of protecting Immanuel, the machines began having concerns of his lack of growth. But they continue to dedicate themselves to protecting Immanuel, stating that they believe he is very cute, and needs to be protected.
After infiltrating the castle, Immanuel is discovered by 2B and 9S, with 9S commenting that this machine must be the forest king. Immanuel is then killed by A2, who appears from above, by impaling the forest king with her Type-40 Sword.