Harry's character could also become more isolated. His new relationship with Voldemort is not something that the wizarding world would easily accept. So he might find himself alone, with only a few people, if any, who are willing to support him. This isolation could make him more introspective, and he might start to rely more on his own judgment rather than the opinions of others.
Another plot development could be the reaction of the wizarding community. When they find out that Harry and Voldemort are mates, there would be chaos. Some might think that Harry has been turned to the dark side. His friends, like Hermione and Ron, would be deeply confused and might even feel betrayed at first. They would have to decide whether to trust Harry's judgment or oppose him, which could lead to a great rift in their friendship.
Harry might be initially shocked. He has been brought up in the wizarding world with certain beliefs and Fenrir is a werewolf, a feared and often misunderstood being. So, his first reaction could be disbelief. He might question how this could be possible considering their different natures.
Yes, there are some fan fictions that explore a romantic relationship between Voldemort and Harry. However, this is a very unconventional and often controversial concept within the Harry Potter fandom, as Voldemort is the main antagonist and his actions are extremely evil in the original story.
Ginny is also frequently paired with Harry in such fan fictions. Given their relationship in the original books, it's a natural extension for fan fiction writers. When Harry finds out Ginny is his mate, it often leads to a more intense and magical exploration of their relationship, with added elements of destiny and true love.
Well, in some fanfictions, Voldemort might see Harry as a tool to be used against his abusers. He could use this knowledge to manipulate Harry into joining his side, thinking that he can offer protection or revenge against those who have wronged Harry.
Harry would likely be stunned. His world has been turned upside down. He might initially be in denial, thinking it's some sort of cruel joke or a mistake. But as he starts to accept it, he may feel a new sense of connection to Blaise. He could start to see Blaise in a whole new light, noticing similarities in their personalities or abilities that he hadn't before. And he would probably be eager to learn more about their shared heritage and what it means for their future together.
A theme that might be present is the power of love and connection. Despite their differences and the difficult situation Harry is in, the bond between Lucius and Harry could be a central theme. Also, there could be a theme of transformation. Lucius's view of the world and his actions might transform as he becomes closer to Harry, and Harry himself might transform from a victim to someone stronger with Lucius by his side. This kind of fan fiction often plays with these complex emotional and character - development themes.
One popular one could be 'The Unforeseen Bond'. In this fan fiction, Harry discovers his mate in the most unexpected of places, like during a Quidditch match when he feels an instant connection to a new student. It has a really engaging plot with a lot of sweet moments between Harry and his mate as they navigate their new relationship while also dealing with the usual Hogwarts chaos.