Tkaa the basilisk brought Trick to the Copper Isles by request of Veralidaine Sarrasri, a demigoddess who has an understanding with the creatures. She wanted to give Aly help in whatever she needed. Trick and the other darkings were instrumental in Aly's cause, and gave her much needed intelligence about the other conspirators and the Rittevon supporters. As darkings can communicate telepathically, Aly was able to garner intelligence much easier.
While with Aly, Trick took the form of a plain beaded necklace around Aly's neck and would whisper in her ear when it had new intelligence. It was very helpful and well-spoken, although it had a few grammatical errors to begin with.