You can try looking on fanfiction websites such as Archive of Our Own. It has a large collection of various fanfics, and there's a good chance you'll find alpha x cid fanfic there.
One good alpha x cid fanfic could be about their adventures together in a fantasy world. They might face various challenges and their relationship could grow stronger through it.
One popular story could be 'The Gore in the Omega's World'. It might involve a conflict between the gore elements, like intense and often violent or grotesque situations, and the hierarchical structure of the alpha, beta, and omega. In this story, the omega might be facing a world filled with gore while trying to navigate their position in the social order.
Well, El Cid has a basis in history. Rodrigo D铆az de Vivar was a real person, but the stories about him have likely incorporated fictional elements over time to make them more captivating.
Well, you should do a lot of research on the existing alpha - beta - omega concepts in different fan fictions and other related literature. This gives you a base to build on. When it comes to the gore aspect, think about what it represents in your story. Is it a symbol of chaos? Or is it a test for the characters? Then, plan your story arc carefully. Have a clear beginning, middle, and end. The beginning could introduce the alpha - beta - omega world and the first signs of gore. The middle is where the conflict really heats up, and the end should resolve the situation in a satisfying way.
Their relationship can be developed through shared adventures. For example, if they go on a quest together to retrieve a powerful artifact. During this journey, they have to rely on each other's skills. Cid's combat and strategic skills combined with Rose's knowledge of the local area or certain magic can bring them closer. They start to respect each other more, which is the first step in developing their relationship.