The Vampire Diaries -- Why Katherine Will Give Damon The Cure
The gang has decided that Katherine stole the cure to make a deal with Klaus, but once Katherine made a deal to give him the cure how could she be sure he’d keep his deal? Klaus is infamous for backstabbing people. She could, however, slip the cure to Klaus, which would turn him human. However, it could also quite possibly turn every person Klaus made a vampire human, as well. It goes to reason that if Klaus dies everyone in his line also dies, then shouldn't it be if Klaus is cured, everyone in his line would also be cured? I’ve also seen it suggested that Katherine took the cure herself, but Katherine became a vampire to protect herself from Klaus. Becoming a human would make it that much easier for Klaus to kill her. It’s why I think Katherine will use the cure on Damon, who made it clear he didn't want to be cured.
We know that Katherine found out about Silas and the cure from Hayley down in New Orleans. But didn’t Damon and Stefan also go down to New Orleans when they were trying to find out how to break the sire bond? So it’s possible Katherine could have been in New Orleans when they visited and knows all about the fact that Elena is sired to Damon. While the people who are still clinging to the fiction that Stefan is the great love of Katherine’s life have hoped if she found out Elena was with Damon she’d come back and get together with Stefan; the last time we saw Katherine she gave up her chance to be free of Klaus to save Damon and pretty much said Damon was her humanity. She also set Stefan up to incur Klaus’ wrath of hatred, so he would forget about the fact Damon had tried to kill him to protect Damon. While when Damon wanted to ruin Klaus’ plan for the sacrifice she warned him not to because Klaus would kill him and everyone he ever met. So it kind of says the real love of Katherine’s life is Damon, not Stefan. So learning that Elena is sired to Damon is not something that would make Katherine a happy camper. What better way to make sure Elena was no longer sired to Damon then by giving him the cure and making him human, again.
Of course if she does use it on Damon you have to wonder if the same thing that could possibly happen if Klaus were cured would happen to all the people that Damon had made into vampires. Would Damon being cured also cure them? If so, that would mean both Caroline and Elena would no longer be vampires, either.
Another reason Katherine might want to use the cure on Damon was because she was very into Damon choosing to be a vampire. Emily said Katherine had been feeding Damon and Stefan her blood for weeks, and since vampire blood only last 24 hours in a human’s body, that means something was holding up Stefan and Damon from becoming vampires. We know she took all choice away from Stefan, so the thing that had to be holding the Salvatore brothers back from becoming vampires was Damon wouldn’t take the final step into choosing to become a vampire. Ultimately, Damon never made the choice, as his father shot and killed him. A fact that I'm sure wasn't lost on Katherine.
Katherine might want to cure Damon so he would have to make the choice of his own freewill to become a vampire. She knows Damon and knows he won’t be happy as a human and will want to become a vampire again. But this time he’ll have to make the choice like she wanted him to do back in 1864.
This could also lead to an episode that might finally tell us Damon and Katherine’s true story. How they first met. How they became lovers. How Damon discovered she was a vampire. And just what happened the last time they were together before she got caught and taken away.
Despite the show claiming that Elena is the protagonist of the show, Damon is the real protagonist. Most of the stories are fueled by his emotions and his suffering. He’s the true heart and soul of the show. The sire bond affected Damon more than it did Elena. He’s the one who has suffered over the possibility that Elena is only with him because of it. Having Damon given the cure and watching him go through the trauma of being human again would offer more story than if anyone else took the cure. Damon said he missed being a human, but giving a choice to be human again, would be prefer to be a vampire? That would be the big journey for him.