Steel Island
Steel Island is the third of the three known islands that make up the archipelago of the Burning Isles inhabitated by mechanical gnomes. Of the three islands, the least is known about Steel.
As recorded by the crew of the Zhalfirin ship Wavecrester the island was barren of life and dominated by a gigantic castle. A whirling æther-storm surrounded the castle's tallest spire. Inside were emotionless, mechanical clockwork gnomes busy building legions of flying servants. All of the creatures, gnomes, clockwork avians and mechanical wasps alike, were constructing a massive dreadnought of metal and sorcery, a destructive artifact the likes of which present-day Dominaria had never seen. It was thought that the unnaturally intelligent gnomes sought only to fulfill their orders and return to their creator by building the biggest artifact to ever walk on the plane. Then they planned to enchant it with flying so they could search for their master.
A confrontation between the Wavecrester and the gnomes ended with the reported demise of the former and the flight on their dreadnought of the latter .
Source
From the Library of Leng: Phyrexian Dreadnought and Prismatic Circle, Duelist #13, October 1996.