Living campaigns are a shared campaign setting with a codified set of rules for the campaign that govern how to build and advance characters as well as how the campaign will handle rules elements of the setting. Campaign staff create, distribute, and manage new adventures in that campaign setting, and quite often administer a player database and promote various products. A living campaign lets players build and advance characters, develop their personalities, and forge relationships. Living campaign games are run at conventions, game days and other gatherings. The rules for character tracking allow a player to take their PC they created for the campaign to any of these meetings and play it in the adventures offered.
In this instance, the OLC or Ohr Living Campaign is an online living campaign centered on using the programs Discord & Roll20.net to create a living, breathing world where multiple game masters and players can come together to build a shared universe. Players can create characters and take them to multiple games to go on different adventures or explore dark dungeons as they present themselves. Always keep in mind however that actions have consequences and those consequences can affect the world around you!