The Stellaris Infernals Species Pack introduces new playable alien races adapted to volcanic worlds, including bird-like, crocodilian, and insectoid forms. It features a new Crisis Path with the Galactic Hyperthermia mechanic, allowing players to terraform stars into red giants and create Entropy Conduits. The DLC also adds four new Civics focused on fire and heat, such as the Fire Cult and Scorched World Heralds. The new species possess the Thermophilic trait, thriving on hot planets and consuming alloys instead of traditional food sources, but they struggle on Arctic worlds. The DLC is available for purchase on Steam.