Deities, Domestic and Foreign
The city of Uruk, being a diverse hub that draws travelers from nearly the whole of the Thurian continent, welcomes the worship of an equally diverse cast of faiths. Some focuses of worship, such as Dagon and Yog, are forbidden due to their perceived nefarious influence on the population, but even the cult of Set is tolerated to an extent within its walls. Like most cities of Shem, it has a patron deity which dominates the religious landscape (Ishtar, in Uruk's case), but other sects have established a notable level of influence. Priests of Mitra, for example, have become vital to the cultural identity of Uruk due to the value placed upon their prowess as healers. This isn't surprising at all, considering the prominence of Uruk's arena and the games held within.
Various deities venerated by the prevailing societies will be detailed. Don't be dissuaded by the prominence of Ishtar's worship in Uruk -- there is a place for adherence to almost any god in this setting. Faith is an important part of cultural identity and should be reflected as such. Although perhaps uncommon, atheism is also an option.
The Gods of the Hyborian Age
The gods of the Hyborian Age were rarely benevolent figures. Most, in reality, would be viewed in later times as little more than demons that preyed upon men for their own enrichment in blood and treasure. The only deities worshipped in this savage time who offered their followers even a modicum of compassion and opportunities to better their own conditions were Asura the Enlightened One and Mitra, the Phoenix Lord. Both of these gods would survive in half-remembered forms into the ages of humanity that were yet to unfold. They would make themselves known to new followers in later times and would evolve into two new faiths, respectively—the dharmic religions of Buddhism and Hinduism in India, the land that Vendhya gave birth to and the monotheistic religion of the Israelites among the descendants of the people of Shem.