The GUARDIAN Alliance is a hidden association of GUARDIANS, together due to survival and finding out GUARDIANS' purpose.
In 1429, GUARDIANS were officially announced as witches/wizards and all had bounties on them. The GUARDIAN population went down dramatically, so they decided to form an underground hideout. Soon, GUARDIANS left the radar, and were never heard from for hundreds of years.
The GUARDIAN Alliance is located underneath Lake Erie, in a chamber that is now an orb of glass protecting a base that has scientific computers inside.