Jarvis can be made more complex by giving him moral dilemmas. For example, if he has to choose between following Iron Man's orders that might be dangerous to others or disobeying to protect the greater good. This would show that he's not just a program but has a sense of right and wrong.
One idea could be Jarvis getting a physical form and having to learn how to interact in the real world like a human. He could struggle with emotions and social cues, creating humorous and touching moments as Iron Man tries to guide him.
However, it might also be one of the Avengers. For instance, Iron Man could be important as he has the closest connection to Jarvis in the original lore. His relationship with Jarvis, both in the fanfiction and in the general Marvel universe, could drive the plot forward, especially if there are elements related to his father, Howard Stark.
One interesting story could be that Edwin Jarvis uses his old - fashioned charm and knowledge to outwit a new enemy that the Avengers are facing. He might offer some insights based on his long experience with Howard Stark and the early days of S.H.I.E.L.D., which the Avengers find invaluable.
One interesting storyline could be Jarvis helping Stark in creating a new type of Iron Man suit. Jarvis' knowledge and Stark's creativity would make a great combination for this. Another could be a story where they face a major threat together, with Jarvis providing crucial intel and Stark using his tech to fight it off.
I think in many fanfictions, the character of Tony Stark stands out. His charisma, his sense of humor, and his determination are really well - captured. And Jarvis is also very well - written in terms of his calmness and his unwavering support for Stark. He's like the voice of reason in many stories, which makes him a very interesting character.
There are many speculations about the man in the iron mask. One theory is that he was an illegitimate son of Louis XIV. He was locked away with an iron mask to hide his identity so as not to cause a scandal or a threat to the king's power. Another view is that he was involved in some sort of political intrigue at the court. However, the exact truth remains uncertain and has been the subject of much debate among historians.
In the story, the man in the iron mask was a mysterious prisoner. His identity was kept secret, and he was forced to wear an iron mask all the time to conceal his face.
Iron Man's origin in the comics involves Tony Stark getting captured and using his engineering skills to create the first Iron Man suit to escape. After that, he continued to improve and develop the technology to become the hero we know.