[@Xiro Zean][@HaltingBlooper]
Greek squad assemble! The more I think about it, this is a pretty odd coincidence. After the defeat of Cronus 3 gods were given lots to rule over:
Zeus- The sky (Technically includes "heaven"?)
Poseidon- The sea
Hades- The underworld

The way our characters are designed:
Ai/Yuu- Heaven
Six- The sea
Krit- The underworld

O.o