Well, in addition to the obvious ones like his friends and family, there could be some minor characters that become important. For example, the shopkeeper Urahara might have some special items or knowledge that could be crucial for Ichigo's recovery. Also, the Visoreds could get involved. They have their own unique powers and experiences. Hiyori might be especially concerned as she has a bit of a connection with Ichigo. They could offer different perspectives on his sickness and how to deal with it.
His friends are very important. Rukia, for sure. She has a lot of knowledge about the spiritual world and could be the one to figure out what's wrong with Ichigo. Orihime with her healing powers also plays a big role. She might use her abilities to ease his pain or at least keep his condition from getting worse. Uryu could also be important as he might use his Quincy skills to analyze what's causing Ichigo's sickness.
Definitely Ichigo's family. His sisters, Karin and Yuzu, would be worried sick about him. They could be the ones to notice his symptoms first and try to take care of him in a more domestic way. His father, Isshin, might also have some secrets or knowledge that could help Ichigo get better. And of course, Ichigo's friends from the Soul Society like Renji and Byakuya might come to check on him and offer their assistance if they think it's something related to the spiritual realm.
Obviously, his brothers are very important. Donatello would be crucial as he could try to diagnose Leo's illness. Raph would be there to provide protection and strength if any threats come while Leo is vulnerable. Mikey would be the emotional support, trying to keep Leo's spirits up.
Obviously Naruto and Kyuubi are the main ones. Naruto, as the protagonist of the original series, is the key character who drives the story forward. His character growth and his relationship with Kyuubi are important aspects.
Hermione would definitely be an important character. She could use her vast knowledge to help Harry throughout the pregnancy, whether it's with medical advice or just emotional support. Another one could be Dumbledore. He might offer his wisdom and protection, guiding Harry through this unusual situation. And of course, the Weasley family, especially Molly. She could be like a mother figure to Harry during this time, making sure he's eating well and taking care of himself.
Videl would be an important character. Since she has been trying to figure out who Saiyaman is, her reaction when Gohan is revealed would be crucial. Also, Goku. Even though he might not be around all the time, his influence on Gohan and his possible reaction to Gohan's double life as a superhero could be interesting. And of course, Chi - Chi. As Gohan's mother, she would have a lot to say about her son being Saiyaman and how it affects his studies and safety.
Hermione would surely play an important role. She could help Harry figure out the details of his inheritance, like deciphering old documents or researching the history behind it.
If it's in a work - related setting, his boss or colleagues could be significant characters. His boss might be understanding and give him time off to recover, or his colleagues could be worried about how his absence will affect the work, which could create some interesting plot points.
Well, Naruto is the key figure in these fanfictions. But characters like Tsunade can't be ignored. As the Hokage, she may give Naruto special tasks or resources that aid in his rise. Rock Lee is also common. His dedication to training and his unique fighting style can inspire Naruto. And Neji, before his death in the original series, could be a character who, in fanfiction, has a change of heart and helps Naruto understand more about the Hyuga clan's secrets, which in turn helps Naruto gain more power and influence.
Neville could play an interesting role. Maybe he could be the one who discovers a new magical plant that is needed for a potion to cure an illness that Ginny or Harry contracts during their marriage. Luna could also be involved. She might come to them with some strange but useful prophecies that help them in a difficult situation, like dealing with a dark wizard who has a grudge against Harry even after the war is over.
Ra's al Ghul is a character that would be significant in a batman arrow crossover fanfiction. As a long - standing adversary of Batman and a figure with a large influence in the criminal underworld, his presence could add a lot of depth to the story. He might be involved in a plot that spans both Gotham and Star City, pulling the strings from behind the scenes. Additionally, Black Canary from Arrow could be important. Her martial arts skills and sonic scream ability would make her a formidable ally in a fight against the combined threats that a crossover would bring.
Sasuke could also be important. He might be initially skeptical of Naruto's Sage Chakra but later see its potential and even collaborate with Naruto. Also, the Great Toad Sage is a key character. It could give Naruto new prophecies related to his Sage Chakra, leading him to new adventures and challenges. Tsunade could also play a role, perhaps in helping Naruto understand the medical aspects of Sage Chakra and how it affects his body.