To make it more clear with examples of each: magic-casters (from various factions), zombies and ghosts, and steam-powered devices and political strife. The City is an old-fashioned place, with a mix of fantasy, horror, and steampunk. The game is polished and fun, with a few nagging flaws that tend to grow more significant in retrospect.
Along the way, Garrett ends up saving the world in his typical laconic fashion. The game gives you the tools necessary for such an unsavoury lifestyle and lets you loose in a world that is full of deserving targets. Thief: Deadly Shadows takes you into the life of Garrett, master thief, and denizen of a strange semi-medieval setting.