The direction of the story: Master has created the Vocaloids, upon the creation of his final one, ghosts from his past come back to take their revenge. His old lab partner seeks to capture the vocalods for purposes unknown. Master equips his vocaloids with the ability to protect themselves and hopefully stop Viper from inflicting harm upon their family.
The story before ep 0 (none of this will be written into the story, only for the clarification of how the history was set up). Viper is trying to capture the vocaloids and master because she's dying and wishes to cheat death. She builds an army of robotic minions to find them and capture them, the minions are not as well built as meiko/kaito, but they're tough enough to kill. Swarms of viper's minions cause great deals of destruction to the lands (causing the government to try and step in, making their creation illegal and actively trying to destroy any they find). This causes master to rush the final stages of miku's creation (her prog