Valhalla if you want fire, black flag if you want pirates

All! Haha! But I enjoyed Odyssey the most out those 3, beautiful world, historically intriguing, and more character customization options. But honestly they're all really great games! Where and when do you wanna go? Ancient Greece, golden age of piracy in the Caribbean, or medieval England?

Is all of them an option?

I think you're gonna want to start with Black Flag if you want a more straightforward and badass experience.

Why don't you buy the first AC and start with it? It's cheap.