From the Description:

“The Ponyarch of the Thousand Mares, Trixie, was both Great and Powerful, and was the best at using magic among all her sisters and brethren. Trixie was unique among the Ponyarchs in that she remembered her origin and creation as a gene-daughter of the Empress – and had some sort of psychic communication with her mother even during her gestation. Trixie’s development of tremendous magic talent may thus have been planned by the Empress, as an intentional attribute gained from her gene-stock.

Trixie thought she would be able to control the Great Ocean of psychic energy that was magic, however her prodigious and careless application of her psychic gifts eventually caused her to fall out of favour with her mother, the Empress, as well as with the majority of her sibling Ponyarchs. Her psychic immaturity, recklessness, and arrogance also caused her own undoing, as it eventually brought damnation and servitude to the Ruinous Powers of Discord upon her.”

…Although Magnus is still more sympathetic.