Central Time Loop

An enormous stable time loop that spans across millennia of Zeta's history. While time travel is an unimaginably difficult feat, so much so that it can basically be considered impossible, conditions lined up just right for one history-altering example. The relevant events are as follows:

1. The Old Age comes to an end when something dramatically boosts the magical ability of countless Zetan residents, most notably those in Terrata.


2. 
   Soul Control magic starts to gain a foothold. The Founding of the Soul Guardians happens as a result.


3. Growing furious with the blatant misuse of magic demonstrated by the Soul Guardians and others with similar arrogance, Shiro founds the Purists in the name of restoring balance. (Zeta's "present time" falls around here.)


4. The Purists capture and eliminate Yeron, who is sent to Rit Shiin.


5. Yeron causes the Great Hereafteran Massacre.


6. 
   Aida is born from the Ghosts and Seraphim lost in that fight.


7. Aida's powerful inventions are lost in the Aida Spacetime Incident.


8. Magical energy from the incident is sent to Zeta's past, even between Realms, and boosts the power of countless unsuspecting beings. This closes the loop.