Anakin Skywalker built C-3PO to help his mother, Shmi Skywalker, with household duties. As a young slave on Tatooine, Anakin created the protocol droid using spare parts. This act was not only a demonstration of his mechanical prowess and intelligence but also served as a personal project that reflected his caring nature.

Building C-3PO also symbolized Anakin's deep connection to machines and his intuitive understanding of technology, which hints at his potential with the Force. C-3PO was intended to be a companion and assistant for Shmi, allowing her to have a more comfortable life.

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In "Star Wars Episode I: The Phantom Menace," young Anakin Skywalker creates C-3PO primarily to help his mother, Shmi Skywalker. Anakin, being a slave, was not allowed to own possessions, but he wanted to give his mother a gift that would be useful. He built C-3PO from spare parts in hopes that the droid could assist her with tasks and provide companionship. Anakin's creation of C-3PO also reflects his innate technical ability and his connection to the Force, which may have subconsciously guided him in constructing the droid. The act of building C-3PO was a personal and heartfelt gesture from Anakin to his mother, showing his love and desire to improve her life under the challenging conditions they faced on Tatooine. This backstory adds depth to Anakin's character and foreshadows his future as a creator and a user of technology in the Star Wars saga.