Bella's actions in the fanfiction might be another cause. Maybe she accidentally says or does something that undermines Jacob's self - esteem. Like if she makes a comment about his werewolf nature in a negative way, it could wound him deeply as it's an important part of who he is.
Isolation is another theme. Given his situation, Regulus often finds himself alone. He can't fully trust his family, and he's also involved in dangerous and secretive activities. This sense of being alone in his struggles is often explored in 'Regulus Black Hurt' fanfiction. It's like he's in a bubble of his own pain, cut off from the world around him.
Well, in the story of Jacob Black and Leah Clearwater, there is a lot of emotional turmoil. Jacob is constantly torn between his wolf nature and his feelings for Bella. Leah, on the other hand, has to deal with the fact that her ex - Sam imprinted on someone else. This causes her great pain. Jacob and Leah are both part of the werewolf pack, and their interactions are often filled with underlying tension and hurt because of their individual emotional baggage.
In addition to the Avengers, there could be original characters created by the fanfic writers. These characters could be doctors or nurses taking care of Black Widow in a secret medical facility. Or they could be other agents who have some connection to her past. Sometimes, even villains from the Marvel universe might interact with her while she's in a vulnerable state, either to gloat or to try and make a deal with her.
Well, in these fanfictions, we see a more vulnerable side of Sirius. For example, in many of them, his time in Azkaban is explored in greater detail. We get to understand the true extent of the psychological damage it caused him, which makes his character more three - dimensional.
One popular 'Regulus Black Hurt' fanfiction might be 'The Lost Heir of Black'. It delves deep into Regulus's inner turmoil and the pain he endures. It often shows his struggle with his family's expectations and his own moral compass. The story is quite engaging as it weaves a complex web of emotions around Regulus.
As I mentioned before, a member of his own wolf pack. In a pack, there can be jealousy and power struggles. If another wolf wants more influence or has a grudge against Jacob, they might be the ones to cause him harm.
In 'Code Black Mario Hurt Fanfiction', a frequent theme is probably the exploration of vulnerability. Mario, who is usually seen as a strong and capable character, is now hurt, so it shows his more fragile side. Also, themes related to friendship might come up. His friends could be trying to help him recover or protect him while he's in this weakened state. It can also be about facing the unknown. The 'Code Black' situation that led to his being hurt might be something new and terrifying that he has to figure out.
Another great one is 'The Scarred Heart'. Here, Bella's words during an argument deeply wound Jacob. The story then follows Jacob as he tries to heal while still being in Bella's orbit. It's a poignant exploration of their complex relationship.
I'm not sure if there are many well - known 'Code Black Mario Hurt Fanfiction' works specifically. You could try searching on some major fanfiction platforms like FanFiction.net or Archive of Our Own. Maybe look for tags related to 'Mario' and 'hurt' to find relevant stories.