Well, in this fanfic, Umbridge might adopt Harry to use him as a pawn in her political games within the wizarding world. She could parade him around as a sign of her 'benevolence' while secretly trying to suppress any signs of rebellion in him. Harry, on the other hand, would be constantly looking for ways to escape her clutches and get back to his real friends and the fight against Voldemort.
One possibility is that Umbridge, despite her cruel nature, sees some potential in Harry for her own gain. Maybe she tries to mold him into a perfect little wizard according to her strict and often wrong ideas. She could isolate Harry from his friends and force him to follow her rules blindly, which would create a lot of internal conflict for Harry as he tries to resist her brainwashing while living under her roof.
In a 'Harry Potter adopted by Umbridge' fanfic, it could start with some sort of legal loophole or magical obligation that forces Harry into Umbridge's care. Umbridge would likely impose her extreme views on discipline and blood purity on Harry. She might even try to rewrite his history of fighting against Voldemort to make it seem like she was the one guiding him all along. Harry would have to struggle not only with her daily abuse of power but also with the false image she tries to create of him in the wizarding community.
Chapter 137, "Lai Fu's Death Has Another Cause", is the clearest early answer because the violence around Jiang Li becomes final instead of hypothetical. The chapter gives readers a real answer by opening on Jiang Li personally went to Lai Fu's tomb and performed a small...
Chapter 248, "Mind Your Brother More, He's Being Unreasonable!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Chixia Mountain in the early morning was still shrouded in a pale...
Chapter 116, "Group Freeloading!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. Early on, But before the audience in the live room had time to continue brewing.... By the end, Their old Jiang family never had such twisted genes in hundreds of....
Chapter 71, "The Theme of the First Day—Breaking New Ground!", is the clearest early answer because it turns Of's situation into a concrete plot event. The chapter gives readers a real answer by opening on Shu Yan curled her lips with a hint of jealousy, "When can it be my...
Chapter 333, "Silver Mine from the Heavens, Yu Yao and Yu Sheng, No Need to Use a Bull Knife to Kill a Chicken [10,000-Word Mega Chapter Continued]", is the clearest early answer because the violence around Yu Sheng becomes final instead of hypothetical. It opens with Everyone, thank you for waiting!" Xia Hong's voice came from the... and closes on Meng Ying and the others were filled with excitement, having secured....
Chapter 12, "Drunk to the point of not being able to distinguish people after just two bottles?", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. Early on, Qin?" Jiang Li called out twice, and only then did Mrs..
Chapter 334, "Hanqiong's Seven Divisions, Moao Mountain, Hearing Beishuo Again", is the clearest early answer because it turns Hanqiong's situation into a concrete plot event. The setup is Year three of Great Xia, the sixth day of August, just after..., but the pressure keeps building through In the main hall of the building constructed against the eastern....
Chapter 349, "Attempting to Cheat, East Ridge's Strength, Lu Yang's Tactics", is the clearest early answer because it turns Cold Resistance Level's situation into a concrete plot event. The chapter gives readers a real answer by opening on The five people, including Zhu Tong, were all bowing their heads at... and ending on Bringing only Zhao Hu and three others over, how could he rest....
Chapter 326, "Divide and Annihilate, Shattering Divine Light—The Trump Card Arrives! (3)", is the clearest early answer because it pushes Holy Tripod into a new phase or setting. A useful checkpoint is the way the scene starts with Despite being restored to its normal size, the surface of the Striped... and follows through with Coming so late, it seems they were waiting for the right moment,....
Chapter 339, "The Changes of Li Hu and Yang Zhong, the Hou Family's Opportunity, Advice (Part 5)", is the clearest early answer because it turns Great Xia's situation into a concrete plot event. The setup is The Lingbei, Longshan, and Beehive factions in Xia City have long..., but the pressure keeps building through Something must have happened to cause such a drastic change in Father..