Perhaps in this fanfiction, Harry is tricked into reviving Voldemort. There could be a powerful dark wizard or creature that manipulates Harry's good intentions. For example, they might deceive Harry into thinking that by reviving Voldemort, he can then truly defeat him in a more final battle. Or maybe Harry's own desperation to end the cycle of fear and death leads him to take a huge risk with magic he doesn't fully understand, and that risk results in Voldemort's revival.
In the 'harry potter revives voldemort fanfiction', it might be that there is a prophecy involved. Harry, being the hero he is, might think that he can control the outcome of the prophecy. He could believe that by reviving Voldemort, he is fulfilling the prophecy in a way that will ultimately lead to the destruction of evil. However, things don't go as planned, and instead, he actually brings Voldemort back to life. Maybe the prophecy was misinterpreted, or there were hidden clauses that Harry wasn't aware of.
Well, one way could be through some dark and misinterpreted magic. Maybe Harry stumbles upon an ancient spell that he thinks will defeat Voldemort once and for all but instead, it backfires and revives him. It could also be due to some sort of interference from a powerful dark object that Harry unknowingly uses in the wrong way.
One consequence could be that the wizarding world falls back into chaos and fear. Voldemort would likely start his reign of terror again, targeting those who opposed him before. He might also try to seek revenge on Harry for initially defeating him.
Perhaps in this fanfiction, Harry discovers some dark secret about the Order of the Phoenix or Dumbledore that makes him lose faith in the side he has always been on. This, combined with Voldemort's manipulation, could lead him to side with the Dark Lord. For example, if he finds out that Dumbledore has been using him all along without his full knowledge, he might be so disillusioned that he turns to Voldemort as an alternative.
Well, it could be that in this fanfiction, Harry discovers some long - hidden truth about the wizarding world that makes him realize Voldemort's motives aren't entirely baseless. Maybe there's a prophecy misinterpretation that leads Harry to think they can work together to fix the wizarding world's problems.
One common plot point is Harry's disillusionment with the wizarding world. Maybe he feels betrayed or mistreated, which leads him to turn to dark magic and revive Voldemort as a form of revenge.
Well, in this fanfiction, perhaps Voldemort adopts Harry because he realizes Harry has some unique power that he wants to control. As Harry grows up, he starts to understand Voldemort's motives and tries to find a way to break free. He could also form unexpected alliances with some of Voldemort's followers who have a change of heart.
One possible plot could be that Harry is somehow tricked into believing Voldemort's cause is just. Maybe Voldemort uses some powerful magic to distort Harry's perception of good and evil. So Harry starts to help Voldemort in his quest for power, thinking he is doing the right thing.
One possibility could be that Voldemort has a sudden change of heart. Maybe he realizes that Harry is the only one who can truly understand his loneliness and power. So instead of killing Harry, he decides to save him from a dangerous situation, like a powerful dark magic that even Voldemort fears could destroy the wizarding world if not controlled, and in the process, they form an unlikely alliance.
Maybe a plot could involve a powerful spell that binds their fates together and they have to learn to live with each other. Eventually, they might start to understand each other's motives and fall in love.
Perhaps Harry joins Voldemort out of a sense of hopelessness. After seeing so much destruction in the wizarding world, he might think that joining Voldemort is the only way to end the war quickly. However, he soon realizes that Voldemort's methods are too extreme and tries to find a way to turn things around from within the dark side.
Perhaps in this fanfic, there has been some major plot twist that makes Harry believe that bowing to Voldemort is the only way to save his friends or the wizarding world. For example, Voldemort may have threatened to kill all of Harry's loved ones if he doesn't submit, and Harry is sacrificing his pride for the greater good.