Memolith: Forsaken by Light

Based on the search results, Remorse: Infected Kingdom appears to match your description[1]. It's a turn-based tactical RPG set in a medieval apocalyptic setting where zombies have taken over medieval towns. The game emphasizes survival strategy, with fragile survivors where every step could be your last, drawing inspiration from XCOM but with a stronger focus on RPG aspects and broader storytelling[1]. Another strong match is Entropy, a dark fantasy turn-based tactical RPG set in a dying, post-apocalyptic world[2]. Players begin in the medieval town of Draenog and must survive a demonic invasion using tactical turn-based combat with a party of up to six characters[2]. The game emphasizes careful positioning, party management, and adaptation against relentless threats[2]. BEAST is also worth considering—a grimdark medieval tactical turn-based RPG torn by plague and military conflicts, where moral choices during battle influence gameplay and have consequences for you and your allies[3]. If you're looking for something with city-building elements alongside the tactical gameplay, combines turn-based strategy with survival city-building mechanics in a medieval setting, where you must build and protect your people against hidden threats[4].