Pactio is a system of magic within the fictional work Negima!: Magister Negi Magi. The word is based on the Latin word "pactiō", the action of making a "pactum" or "agreement". Pactio can also be referred as a "provisional contract." Characters in pactio involve a magic user who can select any companion in the series. Companions involved in a pactio attain abilities related to their personalities. In the remake series, Negima!?, the system is called "neo-pactio."