Well, in 'Cyteen', Ariane Emory is a central figure. She is complex, with her actions driving much of the plot related to cloning and the power dynamics on the planet. Her character development is really interesting as she goes through different stages in the story.
In 'Foreigner', Bren Cameron is the main character. He has to deal with the difficult task of being a diplomat among the atevi. His character is constantly evolving as he tries to bridge the gap between two very different cultures and avoid misunderstandings that could lead to disasters.
However, in 'Downbelow Station', there isn't really a single main character. Instead, there are multiple characters from different species and factions whose actions and decisions together drive the overall plot. Each character has their own motives and goals that intersect in the complex web of the story.
Chapter 576, "The Electronic Pickles are Gone!", is the clearest early answer because it turns Ai Xiaochun's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Tonight, Team Q exceptionally didn't cook.
Chapter 575, "The First Time Threatening Someone Feels Quite Marvelous", is the clearest early answer because it turns Sis's situation into a concrete plot event. The chapter turns that into something concrete by moving from Is there really no way to get any money out?" After some...
Chapter 731, "Ye Chu Died", is the clearest early answer because it turns Bai Lu's situation into a concrete plot event. It opens with Dean, can I really not do it? and closes on She'd been acting off these days.. The key payoff is that the chapter closes with "Why did you come to the sanatorium?
Chapter 707, "I am Daoist Qingfeng", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. The chapter turns that into something concrete by moving from Su Yinwan hadn't finished her dessert but, feeling agitated, had...
Chapter 797, "Bu Fan and Bu Chen", is the clearest early answer because it turns Bu Fan's situation into a concrete plot event. It opens with The night grew deeper, and while waiting for news, Jiang Li dragged...
Chapter 703, "Slap Oneself", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. It opens with Wu Daoshan quietly raised his head to size up Zhao Lang, and sure... and closes on Young Master Gu was intending to back Jiang Li..
Chapter 595, "Four-legged Black Toad", is the clearest early answer because it turns Four-legged Black Toad's situation into a concrete plot event. It opens with Jiang Li steadied himself with support, endured for a while, and then...
Chapter 841, "Isn't this Daniu?", is the clearest early answer because it turns Aunt Zhao's situation into a concrete plot event. The chapter gives readers a real answer by opening on Zhao Lang took the photograph and glanced at it, chuckling, "It...
Chapter 803, "Younger Brother Misses Mom", is the clearest early answer because it turns Mom's situation into a concrete plot event. It opens with Brother, do you think hiding here is a bad idea?" "Don't worry,... and closes on It was as if she had been replaced by a different person..
Chapter 837, "Why did she come?!", is the clearest early answer because it turns Rong Ya's situation into a concrete plot event.