Orcs of the Eternal Zenith (2011)

Publisher's blurb:

The golden hush of midday bakes the rocky slopes of Marred Peak, scorching the hands of the orcish penitents sweltering before their shining prophet, Granalak Searshriek. The orcs, inspired by a visiting, ill-advised missionary, turned to worship the violent, burning aspect of the sun. Guided by divine insight, Searshriek constructs a vast machine of cold iron, imprisoned fey and many-faceted gemstones to harness the noonday sun and tear a hole in reality. This imposing Zenith Engine looms atop the melted rock of Marred Peak, opening a gate into the burning heart of the sun, and threatening to bring endless conflagration into the world.

In the teeming human cities, orcish adherents to Searshriek's damned philosophy infiltrate the hallowed halls of the sun god's faith, spreading the corrupt cancer to the heart of civilization. The secret doctrines of the Eternal Zenith Heresy threaten to undermine the fabric of the church, and cause a violent schism within the ranks, bringing the War of the Burning Light to the cities of man.