Tekton
by Marc SaindonMilenian Empire: retconning the Artificer into 5e Mystara as the Tekton
I'm probably more a fan of Clash of Titans (the original, not the reboot) than of Star Wars. And for me those dated stop-motion effects are sweet and more engaging than modern CGI. One character, Bubo the mechanical owl, is certainly interesting as it presents clock-punk (or myth-punk or sandal-punk?) way before goths discovered brown and took up steampunk.
Greek myth certainly has its share of inventors and mechanical wonders. Daedaleus is the more well-known craftsman (he's an important concept for the Mage: the Sorcerers Crusade rpg), as is Vulcan/Hephaestos (pardon my 'Ancient Grome') who serves as the god of craftsmen. The achievements of both include wonders enchanted thrones, the labyrinth, flying wings, mechanical bulls, animated statues... Other figures include Prometheus (the titan who gifts mankind with fire and other innovations) and Pygmalion (the statue fan-boy). Talos is a colossal bronze statue from a bygone...
While mechanical wonders are rare in Greek myth compared to a divine or magical approach, they are still present. Historical myths are also an inspiration, like Archimedes shield-mirror laser weapon. It wouldn't be a far stretch to include Artificers ("Tektons") in the Milenian Empire. They would be a rare breed compared to Magic-Users and Clerics (already constrained by the rules of the Hollow World) but a handful could still practice their trade.
The Tektons would not start an industrial revolution, as manual labor would be looked down upon by the Milenians due to the cultural stasis and aristocratic bias, and thus Tektons would have a few isolated workshops, and be more eccentric inventors than factory owners. The occasional War-forged ('Automaton') could emerge from such a workshop without breaking immersion: they are extremely rare, but culturally expected.
The Heat ray
Talos
Mechanical bull
Tekton
(Image from: https://gwangipedia.fandom.com/wiki/Bubo_the_Mechanical_Owl)