(The Tower and Sestren)

(1/3) Sestren is the will of the ancients. Sestren is located in a place, between time and space, where no mortal can ever reach it. Sestren controls all Towers.

(2/3) In the Ancient Age, the Towers were called 'Azel Sestrens', or 'Servants of Sestren'. All Towers are tools for Sestren so it can exercise its power on the world. If Sestren is destroyed, the
Towers will sleep.

(3/3) For one to make contact with
Sestren, one must open the gate
to cross the gap in time and space. Sestren can be reached from any Tower, but no methods of opening the gate have ever been discovered.