If Castiel were to be in this crossover, he would be very confused by the walkers at first. He's used to dealing with demons and angels, not undead creatures. But he would quickly adapt and use his angelic powers to protect the group. Rick from The Walking Dead would see Castiel as a valuable asset but also be a bit wary of his otherworldly nature. They would have to learn to trust each other as they both have the goal of protecting the survivors and finding a way to end the chaos in their respective worlds.
The characters from Supernatural would bring their unique skills. Dean, for instance, is an excellent marksman and fighter. He could easily adapt to using guns against the walkers. Sam, with his knowledge of the occult, might be able to figure out if there's a deeper, supernatural reason for the zombie outbreak. Castiel, the angel, could use his powers to heal the injured in Rick's group or even fly over areas to scout for threats. They would add a new dimension to the fight for survival in The Walking Dead world.
One great plot idea could be that the Winchesters from Supernatural find themselves in the world of The Walking Dead. They could use their hunting skills to fight off the walkers in a unique way. Maybe they think the walkers are some kind of supernatural creation at first and try to find a way to cure them like they do with monsters in their own world.
Sam and Oliver would probably start off a bit cautious with each other. Sam, being the more cerebral of the Winchesters, would be interested in Oliver's methods of protecting the city. Oliver, on the other hand, might be a bit skeptical of Sam's supernatural knowledge at first. Dean would likely bond with Diggle over their combat skills. They'd probably exchange stories about their battles, and Dean might even show Diggle some of his unique ways of taking down enemies. Castiel, with his angelic powers, would be a mystery to the 'Arrow' characters. Felicity might be both intrigued and a bit scared of him, but she'd also be eager to understand how his powers work.
In a crossover fanfic, the angels and demons from Supernatural could be involved in The Walking Dead universe. For example, an angel might be sent to Earth to stop the spread of the undead, believing it's part of a grand plan to save humanity. Meanwhile, the demons could be taking advantage of the chaos, making deals with desperate survivors. The Winchester brothers would have to navigate this new dynamic while also dealing with the walkers.
The crossover often brings elements from both the game and comic together. It might feature familiar characters, storylines, or settings shared between them.
Mabel would be excited to meet the Winchester brothers. She might try to get Dean to tell her all his hunting stories and would probably try to knit them some cool accessories. She could also introduce Sam and Dean to Waddles. Dipper would be a bit more cautious around them at first, but as they started working together, he would respect their skills and knowledge. The characters would need to learn to trust each other quickly since they come from different worlds but are facing similar threats.
You can start by looking on fanfiction websites like Archive of Our Own (AO3) or FanFiction.net. These platforms have a vast collection of fan - created stories, and you can simply search for 'Walking Dead Supernatural crossover' in their search bars.
She could interact with Rick. Rick is the leader of the group in The Walking Dead, and he would be very interested in Zoey if she has any skills or knowledge that could help the group survive. Maybe she has some medical knowledge, and Rick would want her to take care of the injured in the group.
Dean Winchester would likely be charmed by Lorelai Gilmore's sass and sense of humor. He might also be a bit protective of her, given his nature. Sam would probably have in - depth conversations with Rory about books and knowledge. Rory, in turn, would be fascinated by Sam's experiences with the supernatural. And Luke would probably be a bit suspicious of the Winchesters at first, thinking they're up to no good in his town.
The powers of the Supernatural characters, like Sam's psychic abilities and Dean's combat skills, would contrast with the more otherworldly powers of the Good Omens characters. Aziraphale's ability to perform miracles and Crowley's demonic powers would be on a different scale. For example, Sam's psychic visions might be able to predict events that Aziraphale and Crowley are involved in, but they might not fully understand how he gets these visions at first.