A rogue demigod who has been corrupted by dark magic could turn into the Dark Lord. This demigod might have been jealous of Percy's fame and power and sought out dark forces to gain more power. Eventually, they become consumed by this dark power and start causing chaos, with the goal of ruling over both the demigod and mortal worlds.
It could be a powerful, ancient Titan who was banished long ago and has now returned for revenge. Maybe Kronos has an even more evil and powerful form that he takes on, becoming the Dark Lord. He wants to destroy the new order of the gods and demigods that has been established since his last defeat.
Well, Nico di Angelo has a good chance of being a main character in this kind of fanfic. His powers over the dead and his somewhat dark and brooding nature could make him a key figure in the fight against the dark lord. Thalia Grace, with her leadership skills and powerful abilities as a daughter of Zeus, would also be a strong candidate. And then there's Luke Castellan. If the fanfic is set in a different timeline or has some sort of alternate reality, Luke could be brought back in a new role, perhaps as a redeemed character who helps in the battle against the dark lord after having once been on the wrong side.
One potential 'Dark Lord' could be Lelouch. Since he already has the power of Geass and is a complex character, it's easy to imagine a scenario where he succumbs to the darker side of his power. His intelligence and strategic mind could be used for more malevolent purposes.
Maybe a powerful wizard who is jealous of the power of both the Shield Hero and the Dark Lord. He wants to eliminate them and take their powers for himself. He could be creating false rumors about the Dark Lord to keep the Shield Hero against him while he plots his own takeover.
One idea could be that the Dark Lord somehow manages to corrupt the powers of the gods. Percy has to find a way to stop this corruption before it spreads across the whole world of demigods. He might have to team up with some unexpected allies, like a group of monsters who also don't want to see the world destroyed in this new, chaotic way.
In Percy Jackson Dark Lord fanfic, the world - building is often an interesting aspect. The dark lord could create their own domain or stronghold, which might be a place full of dark magic and dangerous creatures. This new location would add to the overall Percy Jackson universe. Also, the relationship between the dark lord and the Titans or other ancient powers could be explored. Maybe the dark lord is in league with some of the Titans, or is trying to outwit them to gain ultimate power. And the prophecies in this fanfic could be really different. Instead of the usual prophecies about the demigods' quests, there could be prophecies about the rise and fall of the dark lord, which would drive the plot in new and exciting directions.
It could be another powerful dark wizard who sees the relationship between Sabrina and the Dark Lord as a threat to his own power and plans.
Well, first, Harry would need to study the ways of the Sith. He has to understand his enemy. Then, he could combine his wizarding skills with some new knowledge. For example, he might learn how to use his magic to counter the Sith's mind - control abilities. He could also use his Patronus, which represents hope and light, to drive away the darkness of the Sith. And of course, he'd need to find the Sith's weakness, like in the way he found Voldemort's Horcruxes.
Maybe a group of rogue demigods who have formed a sort of 'dark gamer' cult. They believe that by dominating the gaming world, they can gain enough power to overthrow the Olympian gods and rule over all. They see Percy as a threat to their plans and constantly try to thwart him in the games and in real - life situations.
Stormageddon Dark Lord of All Fanfiction might be a self - proclaimed or fan - created title. It could be that a creative writer in the fanfiction world came up with this name for a character that has some sort of power or influence within their fictional universe. Maybe it's a character who rules over different fan - created stories or has a special place in a particular genre of fanfiction. Without more context, it's difficult to say precisely who or what it is.
He might try to understand the motivation behind it. Maybe he'd think that the author had some issues or was just exploring different ideas. He could approach it from an empathetic angle, but still be firm in his own self - identity and not let it affect him too much.