Alternate timeline, where Golden Oaks Library was never destroyed by Tirek, and where Thorax becomes Twilight’s personal student, instead of Starlight. However Spike is still that one who have found him and along with others helped him reform Changeling Kingdom, and banish Chrysalis.
 
 
He was king of changeling for a while, but only for a while, until he gave throne for his older brother, and moved to Golden Oaks Library, to live there.
 
 
Even before his ref. Thorax was Twilight’s student who was living with Twilight and Spike, but only after the change he began to learn better.
 
 
Twilight does not know that Thorax… has secret feelings for her <3