One way is to base it on the existing blood - related mechanics in the game. Maybe a character discovers a new form of blood transfusion that has the power of 'Blood for Blood'. They could use it to either heal themselves by taking the blood of their enemies or gain new abilities. This would add an interesting twist to the fanfic and stay true to the game's themes.
Another fanfic idea might be to create a prequel story. Show how the 'blood for blood' concept originated in the Bloodborne universe. It could involve the early experiments with blood, the first encounters with the otherworldly forces that led to the creation of this extreme ideology. The story could detail the fall of a civilization or a group of people as they delved deeper into the 'blood for blood' idea, leading up to the state of the world as we see it in the game.
The phrase 'Blood for Blood' in a Bloodborne fanfic could also symbolize a pact or an oath. Characters might swear 'Blood for Blood' to show their loyalty to a cause or to each other. Since Bloodborne has a lot of dark and mysterious factions, this could be a way for members to show their commitment, using blood as a binding force.
First, the atmosphere. You need to capture the dark, gothic feel of Bloodborne. Describe the decrepit buildings, the fog - filled streets, and the sense of dread. Second, the characters. Create hunters or other inhabitants with their own motives and backstories related to 'blood for blood'. Third, the action. There should be intense battles against the terrifying beasts, with lots of blood and gore, in line with the 'blood for blood' theme.
The Old Hunters in Bloodborne is a DLC that expands on the game's lore. It tells the tales of the hunters from the past. There are new areas to explore, like the Fishing Hamlet. It also features new bosses such as Ludwig, the Holy Blade. These bosses are often tougher and more complex than those in the base game, and their designs and fight mechanics are deeply rooted in the dark and twisted lore of the Bloodborne world.
The Old Hunters DLC adds a lot to the Bloodborne story. It delves deeper into the lore of the hunters and the nightmare realm. It shows the origin of some of the strange creatures we see in the main game. There are new areas filled with terrors and secrets.
Blood Curse and Dark Souls belonged to the same game series called Dark Souls. The Bloodborne Curse was the latest work in the series, released in 2015.
Since the Bloodborne Curse was released, several follow-up works have been released, including Dark Souls: Breath of the Wild and Dark Souls: Origins. These games continued the tradition of the Dark Souls series by exploring more game worlds and challenges.
Future titles for the Dark Souls series have yet to be announced, but game developer CD Projeket Red has already announced on social media that they will continue to develop the series and reveal some information about future games.
Well, Gehrman, the first Hunter, would make an excellent main character in such a fanfiction. He has a deep connection to the secrets of Bloodborne. When an Old One crosses over, he would be one of the first to sense the change. His knowledge and skills could be put to the test as he tries to figure out what to do. Also, the Doll could play a significant role. She could be a mediator between the Hunter and the Old One, perhaps trying to understand the Old One's intentions and communicate them to the Hunter.
Well, a cool concept is the power dynamics. In fanfiction, the Old Ones are extremely powerful entities. So, in a crossover, they could disrupt the power balance in Bloodborne. They might introduce new forms of blood magic or madness that the Hunters have never seen before. Also, the cultural clash between the two universes can be fascinating. The Old One's way of existence might be completely different from what's known in Bloodborne, leading to all sorts of interesting plot developments.