Luke's story wasn't complicated. It came straight from the series Shadowhunters.
Many, many years ago, the Angel Raziel used the Mortal Cup to create Shadowhunters—hybrids with both angel and human blood.
Possessing angelic bloodlines, Shadowhunters took it as their duty to hunt demons and protect the human world.
Three people in their history were worth mentioning: Valentine, Luke, and Jocelyn.
Valentine and Luke were best friends. Luke and Jocelyn were partners. Valentine and Jocelyn were lovers.
Valentine was paranoid and obsessed with blood purity, leading him to slaughter Downworlders like Seelies and Warlocks indiscriminately.
This behavior severely violated the Accords. He went on to question the validity of the Accords themselves, plotting to steal the Mortal Cup to create more Shadowhunters.
Since Angel Raziel created the first Shadowhunter, using the Cup to make more had been strictly forbidden. Although his peers knew Valentine's original intention was to prevent meaningless sacrifices, they could only advise him against it. But their words only fueled his rebellion.
As Valentine's ideology became increasingly extreme, Luke and Jocelyn found themselves falling for each other while trying to comfort and persuade him. Both restrained their feelings, but Valentine misunderstood, believing they were having an affair. This pushed him over the edge. He went so far as to modify himself with the very demon blood he despised to become a stronger warrior.
He set a trap for Luke, betraying his oath as a parabatai (warrior partner) and his own faith.
Valentine lied, claiming some farmers had gone missing due to werewolves, and asked Luke to provide backup. But when Luke rushed in, Valentine locked the door behind him.
Although Luke survived, he was turned into a werewolf.
Valentine wanted to create a brand-new army of Shadowhunters. Knowing the Mortal Cup would be displayed during the signing of the Accords to show off the Clave's power, he stormed the Hall, killing countless Shadowhunters and Downworlders who stood in his way, and seized the Cup.
However, thanks to the resistance of Jocelyn and her parabatai Luke, the Cup didn't end up in Valentine's hands. His conspiracy failed, and he supposedly died.
Luke accepted his identity as a werewolf and became a police officer. Jocelyn gave up being a Shadowhunter.
The story of the Shadowhunters series begins after all this. The heroine is Jocelyn and Valentine's daughter, Clary.
Find the Cup, save Mom, fight Dad—that's basically the plot.
The heroine is beautiful—stunningly so, in Shane's opinion. But her personality is problematic. Too self-centered, massive double standards, and a total "Mary Sue" hypocrite!
"So, how's the story?" Shane drained his glass of champagne and asked with a smile.
Olivia's lips curled up, her gossip radar pinging. "So, did Luke and Valentine's girlfriend, Jocelyn, get together?"
"No."
"Why not? Isn't Valentine dead?"
"Restrained by honor, stopped by reason, I guess."
Shane felt sorry for Luke. Putting aside their relationship with Valentine, everyone believed Valentine was dead. Jocelyn took her daughter and started a new life, and Luke watched over them constantly.
To Jocelyn's daughter, Luke played the role of a father throughout her upbringing.
Later, when Jocelyn was incapacitated and her daughter stumbled naively into the Shadow World, it was Luke who guided her, cleaned up her messes, and helped her grow. Finally, when they managed to wake Jocelyn up and their relationship seemed ready to evolve... Jocelyn died.
"Restrained by honor?" Olivia scoffed, clearly disagreeing. She changed the subject. "What are you going to do when you see him tomorrow?"
"Chat, make friends. If he doesn't mind, watch the werewolf transformation process. And... if luck is on my side, maybe I have a way to turn him back into a human."
"You can turn a werewolf back into a human?"
Olivia was skeptical. She could accept the legend of humans being bitten and turning into werewolves, but reversing it? How was that possible?
Shane shook his head. "Just a theory. Whether it succeeds depends on luck."
His theory involved Sealing Jutsu.
Sealing Jutsu uses seals to lock away an opponent's chakra. Powerful sealing techniques can even restrict the opponent's body or soul.
Contract Seal: Capable of severing the contractual relationship between a summoner and their summoned beast.
Assuming the bloodline connection is equivalent to a contract, could sealing or severing the link between the turner and the turned revert the victim to their pre-contract state? To before they were turned?
Evil Sealing Method: A sealing jutsu that uses cursed seals to lock away an opponent's chakra.
Chakra is the perfect fusion of physical and spiritual energy. Assuming the werewolf power is similar to chakra, if it's sealed and the power can't be used, the user won't lose control. This would solve the symptoms, if not the root cause.
Five Elements Seal: Seals away demons or spirits.
Shane felt this seal was better suited for possession types, like ghosts or demons. Once sealed inside the possessed body, unable to leave, the trickiest part of possession—the spirit escaping—would be solved.
The Contract Seal felt more appropriate for vampires, who had a strict hierarchy where superiors held absolute control over their progeny.
But the Evil Sealing Method had a higher chance of success for werewolves.
In Naruto, Kakashi used the Evil Sealing Method to suppress the Cursed Seal of Heaven that Orochimaru placed on Sasuke.
The Cursed Seal's power was external. The werewolf venom in Luke was also external. If luck held, and the Naruto system interacted compatibly with this world's rules, it could indeed turn Luke from a werewolf back into a human.
Even if it wasn't a permanent cure, it could be a functional one.
Solving the symptoms was enough. After all, Shane was the only one who knew Naruto sealing jutsu. As long as Luke was careful not to break the seal through other means, a lifelong suppression was practically the same as a cure.