They are something from the Negima manga. to barrow from the wiki "A Pactio is a magical contract used by many mages in Negima. The word is based on the Latin word "pactiō", the action of making a "pactum" or "agreement". The word 'pactio' is also fairly often called a "provisional contract." Pactios can be created with any magic user, although not all magic users can create a magica circle. The partner with whom the pactio is formed attain abilities related to their personalities." A Pactio card is the symbol of the Pactio.