The identity and background of Lucy's father were described differently in different documents. In document 1, Lucy's father was an employee of a fallout shelter company. He took Lucy away during a mission and became the manager of a fallout shelter. He had launched a nuclear bomb to destroy Shayin City and was taken away by Mrs. Flame for interrogation. In document 3, Lucy's father was Jorde Hartfilia, a wealthy businessman. However, after his wife passed away, his relationship with his daughter became bad, causing her to run away from home. In document 5, Lucy's father was a man who abandoned Lucy's youngest daughter in Ode to Joy 5 in order to remarry quickly. In other documents, Lucy's father's identity was not mentioned. In summary, there were different descriptions of Lucy's father's identity and background, and it was impossible to get an accurate answer.
Lucy's father's relic was a key, the Star Sprite King's key. This key could open the gate of the star spirits and had the ability to transmigrate. At the same time, this key was also the hand of a clock.
Well, it depends on the specific fanfiction. Some fanfictions might make ACNOLGIA Lucy's father for the sake of a unique plot. Others may not follow this idea at all. There are so many different ways fanfiction writers can take the story, but it's definitely an interesting concept that some writers have explored.
It could be a heroic character she meets during her quest. Maybe a powerful wizard or a brave knight who has a brief but intense encounter with Lucy, leading to her pregnancy.
One implication could be a change in Lucy's status. If ACNOLGIA is her father, she might be seen as more powerful or more dangerous.
I'm not sure specifically as there could be many different interpretations in such a fanfiction. It might be a story where Naruto somehow becomes the father figure to Lucy, perhaps in a crossover universe where the Naruto and Fairy Tail (since Lucy is from Fairy Tail) worlds collide, and Naruto takes on a paternal role for some convoluted plot reasons.
A great storyline could be that her real father is an OC time - traveling mage. He accidentally travels to the future and falls in love with Lucy's mother. But then he gets trapped in the future and has to watch his daughter grow up from afar. This could lead to some really emotional scenes when they finally meet.
Natsu is a very likely candidate. Their relationship in the original series is quite close and has a lot of potential for a romantic sub - plot that could lead to him being the father. Their chemistry would make for an interesting story as they navigate parenthood.
Well, if we're following the common ships in the Fairy Tail fandom, Natsu could be a likely candidate. Their relationship is very close and there are many hints of a deeper connection between them in the original series. It would make for an interesting story as Natsu would have to grow up a bit to take on the role of a father.
Gray could also be a possibility. He and Lucy have a friendly rivalry and there are moments where their relationship could be interpreted as having deeper feelings. It would be an interesting twist if Gray was the father, as it would change the dynamics between him, Natsu, and Lucy in the fanfic.
Well, start with the big fanfiction platforms. Fanfiction.net has a large collection of various fanfictions. Look for the Naruto or Fairy Tail sections and then search for the specific title. Another option is AO3. It's known for its wide range of fan - created content. Sometimes, you might also find relevant links on Naruto or Fairy Tail fan forums. People often share and discuss interesting fanfictions there.