From the introduction:
In this world, the existence of Digimon has been public knowledge for decades, but was generally thought of as an entertainment franchise. Recently though, Digimon have begun to appear in the Real World, and a special device called a Vital Bracelet is rolling out today, enabling humans to act as Tamers and keep the more malevolent Digimon in check. Surprisingly, humans have taken these events in stride. Many are looking forward to becoming a Tamer, and most can tell the good Digimon from the bad, meaning few have grudges against Digimon in general. With so many Tamers, and few motivating forces, it is unlikely this world will be put in jeopardy. Whether you seek to change that, or simply enjoy your time here, is up to you.