A Construct was an incredibly powerful machine, powered by the Secret Art, originally created by Rulke. It had the ability to trace the Way Between the Worlds, as well as fly.
After Rulke's death in 2 ATM, the Aachim attempted to recreate his brilliant creation, however, failed to learn the secret to make their constructs fly. Tiaan Liise-Mar and Matah Malien, however, discovered the long lost secret of flight in 206 ATM and renamed constructs; Thapters.
Thapters became instrumental in humantities efforts to defeat the lyrinx in the later years of the Lyrinx War, with a number of people trained in becoming thapter pilots.