A powerful dark wizard who has somehow managed to tap into Asgardian magic could be the main antagonist. He might have found an ancient artifact that gives him access to Thor's powers but twists them into something dark. He wants to rule both the wizarding world and Asgard, and sees Harry and Thor as the biggest threats to his plans.
It could be Loki. Since he has a knack for causing trouble, he might find a way to cross over to the wizarding world. He could manipulate the dark wizards and use their magic for his own devious plans. Maybe he wants to steal the Philosopher's Stone to gain immortality and use it to take over Asgard as well.
Perhaps a new character, a hybrid of a dark wizard and a Frost Giant. This being could be created by a dark ritual that combines the cold magic of the Frost Giants with the dark arts of the wizarding world. He would be after the power of both Thor and Harry, aiming to create a new realm where he is the sole ruler, using the powers of both Asgard and the wizarding world to his advantage.
Chapter 925, "Elder Wu's Last Disciple!", is the clearest early answer because a shaky connection becomes usable in the plot. It opens with The man wearing glasses seated in the prominent position pointed to... and closes on Don't even know who Wu Pei is?.
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....
A practical answer is Chapter 13, because it turns the idea into a concrete scene. The chapter opens with Sensing that something was off with Jiang Yan, Jiang Yan dismissed the..., adds pressure through He probably had a good guess who it was., and ends on How could this happen..." Lin Manru.
Chapter 841, "Isn't this Daniu?", is the clearest early answer because it turns Gu Yu's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Zhao Lang took the photograph and glanced at it, chuckling, "It...
The best chapter pointer here is Chapter 18, "Criminal Law stipulates that kidnappers will be imprisoned.". It opens with In the corner, a girl in a black dress sat quietly, holding a glass of... and closes on Hurry home, what is a young lady like you doing running to a place like....
The best chapter pointer here is Chapter 41, "Actually Still the Museum Director?!". It opens with The live streaming room suddenly boiled over again. and closes on In contrast, Wen Jiaojiao didn't have such awareness..
Chapter 929, "Award Ceremony", is the clearest early answer because the buildup finally cashes out in a real clash. A useful checkpoint is the way the scene starts with The Golden Statue Award is considered the most prestigious award in...
Chapter 820, "He’s actually even harder to coax than Buchen!", is the clearest early answer because it turns Waa's situation into a concrete plot event. The chapter gives readers a real answer by opening on Today, he was particularly cautious with his eating, even sipping his...
Look to Chapter 28 for the clearest answer. It begins with The next evening, Jiang Yan drove home seething with rage., keeps building through Before he even entered the dining room, he shouted angrily, "Lili, you did..., and lands on Lili then kicked his knee hard..
If you want the clearest chapter reference, go to Chapter 21. Early on, Jiang Li's clear and logical explanation had everyone stunned in place.; later, the chapter leans on Jiang Yan had wanted to defend Su Yinwan since his sister's temper in the....