They had the same nature of elements as that of the beads inside the crusts. They were only formed due to the true knowledge of the principles of the laws of creation.
Aside from the guardians created by the universe itself, only cosmic divines could also create lasting pure essence guardians. Celestials could produce high essence guardians which would loose their potent powers with the passage of time. Gods could materialize low essence guardians. Hegemons couldn't create true elemental guardians but they could conjur strong replicas, and could also confine an existing principal for later purposes.
