Man, the cast in 'Urban God of Medicine' is sprawling, but a few stand out. Ye Tian is the clear protagonist—dude starts off as an ordinary medical student but gets caught up in the world of ancient cultivation and modern medical arts. His journey from zero to hero is the core thread. Then there's his romantic interest, Su Qingxue, who's not just a damsel; she's got her own corporate battles and family drama that tie into Ye Tian's world. Lin Wan'er, another key figure, is a fellow cultivator and often serves as a rival-turned-ally, complicating the power dynamics.
You also can't forget the villains like Zhao Wude, who represent the corrupt medical-cultivation conglomerates trying to control everything. They're the ones constantly throwing obstacles in Ye Tian's path. Some side characters, like his mentor Old Man Zhang, pop in and out to drop crucial knowledge or hidden techniques. Honestly, keeping track of everyone can be a bit of a headache during some of the more crowded arcs, but the core group around Ye Tian is pretty well-defined after the first hundred chapters or so.
Sometimes I feel like the novel tries to introduce too many 'important' characters too quickly, and a few just fade into the background.