The Ministry of Magic could also be the main antagonist in this case. If the Ministry is corrupted or under the influence of dark forces, they could manipulate Harry's friends. They might convince his friends that Harry is a danger to the wizarding world order, and his friends, being naive or misinformed, end up betraying him.
A new, powerful and mysterious dark wizard or witch could be the main antagonist. This character could have some hidden agenda that involves breaking Harry's support system. They could target his friends, use their weaknesses, and make them betray Harry for their own gain or to further the dark wizard's evil plans.
A practical answer is Chapter 10, because it turns the idea into a concrete scene. The chapter opens with Qiao's shocked face struggle to recover, Lin Manru also tasted for the..., adds pressure through The young man stood motionless, his gaze fixed on the girl below, and..., and ends on Who was.
Chapter 29 is the strongest chapter-level answer because it starts from Big brother, it's me..." The shadow suddenly spoke and it was Jiang... and follows through on Big brother, are you unwilling?" His mournful expression seemed to signal....
The best chapter pointer here is Chapter 51, "The Great Lodging Competition". It opens with Oh, okay." After uttering two syllables indifferently, Jiang Li bent down... and closes on If I opened a bar here, wouldn't I become a savior?" Jiang Yan was....
Look to Chapter 49 for the clearest answer. It begins with My phone!!!" Jiang Yan's roar echoed continuously through the mountains in..., keeps building through Watching helplessly as his latest-model phone was taken away by a..., and lands on Thinking this, Jiang Yan marched forward, pulled Jiang.
Chapter 13 is the strongest chapter-level answer because it starts from Sensing that something was off with Jiang Yan, Jiang Yan dismissed the... and follows through on How could this happen..." Lin Manru didn't want to hear any more of her....
The best chapter pointer here is Chapter 15, "The Autistic Teen Jiang Shixu". It opens with Jiang Shixu woke up from those nightmares filled with blood and darkness,... and closes on Since she didn't move, Jiang Shixu also stayed put, and the kitchen, which....
The best chapter pointer here is Chapter 48, "All the Bitter Teas Have Been Taken Away". It opens with He Yun felt guilty for initially ignoring Jiang Li on purpose, and with... and closes on Besides, everyone's phones will be replaced with special smartphones....
The best chapter pointer here is Chapter 51, "The Great Lodging Competition". It opens with Oh, okay." After uttering two syllables indifferently, Jiang Li bent down... and closes on If I opened a bar here, wouldn't I become a savior?" Jiang Yan was....
Chapter 48 is the strongest chapter-level answer because it starts from He Yun felt guilty for initially ignoring Jiang Li on purpose, and with... and follows through on Besides, everyone's phones will be replaced with special smartphones....