In the 'Arknights Who Is Real' event story, it might introduce new characters or expand on the backstories of existing ones. The plot could revolve around a series of investigations or encounters that force the characters to face the concept of reality. For example, there could be illusions or false identities that the operators need to decipher. This event story may also be related to the overall lore of Arknights, adding more depth to the game's world - building.
One interesting Arknights fanfic could be those that explore the backstories of the operators in more depth. For example, a fanfic might focus on the early days of Amiya's leadership and how she coped with the various challenges. Another type could be the ones that create alternate universes where the factions have different relationships. Some fanfics also center around the relationships between different operators, like the friendship or potential romances.
The determination of the real protagonist in the Arknights event story is subjective. Different players might consider different characters as the main focus based on their actions and influence on the story's development.
I'm not sure specifically what the 'Black Steel Driver Story' is about as it could be a very specific or even a made - up, local story. It might be about a driver who has something to do with black steel, perhaps a character in a fictional work who drives a vehicle made of or related to black steel.
Well, sometimes it could be a reward for solving a complex puzzle or as a gift from a mysterious ally. It really depends on the specific anime story's rules and plot.
Since I don't know the exact 'Black Steel Driver Story', I can't say for sure. But likely, the main character would be the driver. There might also be other characters like the people he interacts with at his work, such as the people loading and unloading the black steel, or his boss who assigns him tasks related to the black steel transportation.