The combination of two popular and dark themes. 'The Walking Dead' is all about survival in a post - apocalyptic world, and vampires add an extra layer of mystery and danger.
Make their abilities fit within the context. Their enhanced speed and strength can't be too overpowered. They should still struggle against large groups of walkers. Also, their vampire senses could be both a help and a hindrance. For instance, they can smell blood from afar, but that might also attract unwanted attention from both walkers and other survivors.
There's a story where a vampire is actually an ally in the fight against the walkers in the 'The Walking Dead' universe. It shows how the vampire's powers, like enhanced strength and speed, are used to protect the group. This kind of fanfiction often plays with the idea of different supernatural elements co - existing in the already chaotic post - apocalyptic world.
Michonne does die in the comics. The circumstances surrounding her death were quite dramatic and had a significant impact on the story's progression. It happened during a major conflict with other characters.