This ghastly boss-monster appears in Astromythos: Lair of the Spider Lord and Astromythos Book Two. His bronze exoskeleton is encrusted with giant jewels. In his orbital dark laboratory, he strives to create stars of evil to help him seize control of the galaxy. His 5e-compatible stat block is found only in Lair of the Spider Lord, which is available here on the Astromythos shop page: https://www.astromythos.com/shop/pre-order-astromythos-lair-of-the-spider-lord