In a fanfiction, Harry Potter himself could use his skills in Defense Against the Dark Arts to fight the zombies. He would be amazed at the survival skills of the characters from The Walking Dead. Daryl, for example, could teach Harry some of his hunting and tracking skills. The Mashone could bring in their own cultural elements. Maybe they have a special way of communicating that helps in coordinating between the two groups. They could also have unique magical abilities that are different from what's seen in the Potter world and use them to everyone's advantage.
Hermione would probably be very interested in studying the situation in The Walking Dead world. She might try to find a scientific or magical explanation for the zombies. The survivors from The Walking Dead, like Rick, would be initially skeptical of the magic but would soon see its value. The Mashone could act as mediators, helping both sides understand each other. For instance, they could explain the ways of the Potter world to the survivors and vice versa.
If we think about Snape, he would be a complex character in this crossover. He might initially think the survivors of The Walking Dead are unworthy of his help. But as he sees their determination, he could change his mind. The characters from The Walking Dead would be in awe of the magic potions and spells. The Mashone could be a group that has a deep understanding of both magic and survival. They could help the Potter characters understand the harsh reality of the zombie - infested world and also help the Walking Dead characters appreciate the power of magic.
Chapter 386, "New "Game" Mode", is the clearest early answer because it turns Shang Shaobai's situation into a concrete plot event. It opens with Seeing Shang Shaojing's somewhat pale face, Su Yinwan's heart felt a... and closes on After a long time, he finally spoke..
Chapter 592, "The Secret of Dragon Ridge Lake", is the clearest early answer because the hidden truth stops feeling like mere subtext. The chapter turns that into something concrete by moving from Hmm?" Jiang Li's unexpected question left Zhao Lang somewhat...
Chapter 402, "The Survival Game Officially Begins!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. The chapter gives readers a real answer by opening on What kind of face was it?
Chapter 294, "President, This Kid Says He Is Shiguang", is the clearest early answer because it turns President's situation into a concrete plot event. Early on, Speak of the devil, and he shall appear.. By the end, You, have you come of age yet?.
Chapter 231, "vLet Me Check Out the Strength of 5000", is the clearest early answer because it turns Huo Ziyang's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Huo Xuan felt a burst of secret delight in her heart.
Chapter 603, "Met Uncle Beggar", is the clearest early answer because it turns Jiang Mingyu's situation into a concrete plot event. The chapter gives readers a real answer by opening on Our family's ships have flipped, but it should be just two of them."...
Chapter 652, "He's Gu Shengrong's Grandson?!", is the clearest early answer because it turns Gu's situation into a concrete plot event. The chapter gives readers a real answer by opening on The propellers lifted off again, and Team Q was already on their way...
Chapter 228, "Younger Brother is the Number One Hater?!", is the clearest early answer because it turns Younger Brother's situation into a concrete plot event. The chapter turns that into something concrete by moving from Huo Ziyang had not stepped out of the house for a whole week.
Chapter 379, "Is This the Way Huaxiu Treats Its Guests?", is the clearest early answer because it turns Song Man's situation into a concrete plot event. It opens with Song Man chuckled twice, evidently displeased, and then positioned...
Chapter 594, "Raising Soldiers for a Thousand Days, Using Them for a Moment", is the clearest early answer because it turns Everyone's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Thinking of this, Jiang Yan squeezed himself next to Zhao Lang while...