In Book 7 the Chenya of Riddle’s dream says that Trey has always refused to join his and Riddle’s band and Trey explains, “Arts and music are required at arcane academies to help bolster the students’ imaginations, but I’d never take those subjects if I had a choice,” and struggling with his imagination is possibly a theme for Trey:
After he loses his glasses on the journey to the dream Idia reminds him, “Dreams are worlds of imagination…This could all be solved if you envisioned yourself being able to see without glasses,” and Trey responds, “Easier said than done.”
Trey struggling with his imagination has also been mentioned in his third birthday vignette: when asked what he hopes to do in the next year Trey responds,
Deepen my appreciation of the arts, I suppose? Whenever I return home I always make sure to visit the art museum. I don’t really care about paintings and statues either. I’m doing it more out of necessity.
I have to do SOMETHING about my grades in art. The written exams are one thing, but besides that I struggle with any tasks requiring imagination. Quite a fatal flaw for an aspiring mage, wouldn’t you say? I need to get a handle on it.
During Vargas camp Trey uses magic to deflect a large stone that is thrown at him by the Vargas Monster, casts a barrier spell and uses magic to freeze grass.
Trey uses magic to muffle sound and an unspecified attack magic during Playfulland to break things apart.
Trey also uses an unspecified form of attack magic in Book 7 against darkness summoned by Malleus and against Malleus himself.
When asked what is it he likes about being able to use magic he says he uses it to keep eggs from dropping to the floor.
Trey uses clothes-changing magic in Book 7, and wind magic during the Nightmare Before Christmas event to keep Sally from hitting the ground after she jumps out a window.
It is possible that Trey also uses wind magic in Book 7 in order to cushion his landing after a fall.
Twisted Wonderland Reference Note 