Adventure Time Theory: The Grass Sword’s Curse

Since the episode Breezy aired yesterday, I think I’ve figured out the exact nature of how the Grass Sword is affecting Finn. Obviously this is going to contain massive spoilers of episodes from Blade of Grass onwards, so make sure you’re all caught up if you’re going to read this.

To put it simply, the grass sword draws its power from the emotional stability of the wielder. When Finn is emotionally stable, he can control the sword’s power. When he’s emotionally unstable, the sword’s power will start to overwhelm him, and the outcome won’t be pretty.

Starting with the episode Blade of Grass, it’s pretty obvious that the sword is linked to Finn’s emotions. The sword gives him no problems until he has a nightmare of it consuming him, and after that, his fear causes him to lose control over its actions.

The grass sword follows Finn around and does whatever possible to bind to his arm. Many of Finn’s actions make it seem like the sword is behaving independently from the rest of his body, and it even starts slicing things into the shape of his head.

But once he stops fearing the grass sword’s curse and accepts that it’s attached to him, Finn gains control over its actions.

Fast forward to Escape from the Citadel, when Finn refuses to let go of the escaping vessel that’s carrying his dad. He’s holding on as hard as he can, and his shoulder is bulging like the force is going to rip his arm right out of its socket. But no sane person would hold on so tight they would lose their entire arm before losing their grip, right?

And then the grass sword comes in. It transforms itself into a massive arm, holding on with all of its might. It held on so hard that it broke off of Finn’s body and took his arm off with it.

Finn was blinded by confusion, anger, and determination, so he absolutely refused to let his dad leave him again. As a response, the grass sword grew more powerful than ever and tried to help Finn get what he wanted, but in the end, he ended up without his dad or his arm.

While the grass sword left Finn physically, its curse remained attached to him. The curse was able to convert his emotions into power, and use that power through the physical sword. But with the sword gone, it had nothing left to control. That is, until a drop of the Citadel Guardian blood landed on Finn’s arm stub.

While the blood’s healing magic was powerful, it wouldn’t be able to directly grow his arm back. To quote Madam Pomfrey from Harry Potter and the Chamber of Secrets: “I can mend bones in a heartbeat, but growing them back…Regrowing bones is a nasty business.” In fact, even when the Lich was covered in the healing magic, it didn’t grow back its broken horn. Rather, the rest of its body grew muscles, flesh, and skin.

The Guardian blood couldn’t heal back Finn’s arm, so instead, it bound itself to the grass sword’s curse. This was the source of the flower on Finn’s arm stub. So while the curse could no longer control the grass sword with its power, it could instead control the healing magic of the Citadel Guardian blood. And remember, this magic was powerful enough to EASILY DEFEAT THE LICH. And the grass sword’s curse, the thing that was attached to Finn’s emotions, gained control over it.

In the episode The Tower, Finn’s distress over the loss of his arm reaches its peak, and he becomes filled with thoughts of anger and revenge towards his dad. And just like before, when Finn refused to let go, the grass sword’s curse grew dangerously powerful. With its healing magic, it was able to generate a telekinetic arm for Finn to control. It’s pretty clear that the sword’s curse is behind this, as just like in its first appearance in Blade of Grass, it sliced an apple perfectly in half.

“That apple slicing is too perfect… demonically perfect.”

The telekinetic abilities were likely there for the same reasons as sword’s ability to control itself before Finn accepted its bond to him.

So just like before with the massive grassy arm, the grass sword’s curse used Finn’s emotional instability to generate a massive amount of power that would allow him to blindly pursue his goals without regard to common sense. With his newfound powers, Finn decides to build a tower into space so he can find his dad and rip his arm off to keep for himself. Obviously, there’s absolutely no way such a plan could work, and yet Finn keeps on trekking upwards, happily singing “Daddy’s got an arm, and baby’s gonna harm his arm by tearing it off his dad.”

And the tower grows taller and taller, until it appears that Finn has actually managed to build it up into space and he is at risk of suffocating up there. In fact, the only reason that he didn’t keep on going was that Princess Bubblegum had flown up there to rescue him. Had it not been for that, it seems incredibly likely that Finn actually would have died up there.

Once Finn realizes that revenge wouldn’t help make him feel any better, the unstable telekinetic arm disappears.

Fast forward to Breezy, in which Finn has reached a point of desolation. The flower on his arm begins to die, and Doctor Princess says that he needs to be more emotionally upbeat in order to keep it alive. So Finn, hoping to have fun, goes around kissing every princess he can find, hoping it’ll make him feel better. Obviously, it doesn’t.

Eventually, Finn realizes that his exploits have been making him no happier, and an odd hallucination of Princess Bubblegum telling him “my hero arise, let love be your guide” causes his arm to grow back.

As a side note, I’ve thought for a while that Finn and Princess Bubblegum will end up together. “Too Young” showed how much chemistry they have when they’re at the same age, and “Too Old” showed that they have almost none when there’s a notable age gap between them. Besides that, Finn has been aging while Princess Bubblegum hasn’t, and ever since the Flame Princess arc when Finn finally dropped his crush on Princess Bubblegum and let their friendship grow without such a barrier, they seem to have become a lot closer.

Finn obviously has a lot going through his mind at this time. All the time he’s spent chasing princesses was to find happiness and end his emotional desolation. After having hurt Breezy’s feelings by not returning her love for his flower, he realized that he was no closer to happiness than before. I think that his hallucination of Princess Bubblegum caused him to realize that he doesn’t need to force his life to go somewhere in order to find happiness, but rather, he just needs to “let love be [his] guide” and accept that he’ll find happiness when it comes to him. In fact, Jake told him to follow his heart at the beginning of The Tower, but Finn was too distressed about his dad in order to actually understand what his heart wanted.

To recap, when Finn lost control over his emotions, the grass sword’s curse was able to amplify this to the point where he put his own life at risk. With the powerful grassy arm or the ghostly telekinetic one, Finn was able to pursue his goals before thinking about whether or not doing so would be the best idea. The heavy costs of Finn’s instability caused him to lose his arm and almost die up in space.

On the other hand, when Finn showed acceptance of his the state of his life, the curse’s power was able to help him. When he accepted that the grass sword had permanently attached to him, he was able to control the weapon freely. And when he accepted that he couldn’t force himself to find happiness and instead should just let his emotions guide him, the curse’s power allowed him to COMPLETELY REGROW HIS ARM BACK.

It’s interesting how blind determination gave Finn a fake, unstable apparition of his arm, but acceptance allowed him to grow back the real thing, which he had full control over. Just a nice little touch saying something along the lines of “revenge seem like it feels good but it’s not actually feeling good”.

So basically, the curse punishes blind determination, but rewards acceptance. For a character like Finn, this could be seen as somewhat dangerous. At a time when he has just gone through an emotionally wounding encounter with his father and he’s going through the tough stages of teenage emotions, the grass sword’s curse will likely be very important to Finn’s growing maturity and development as a character.

As for the small thorn visible on Finn’s hand at the end of Breezy, it’s most likely there to show that the grass sword’s curse still lingers with him, just like how the flower did.

I think it would be kind of poetic if the grass sword regrew from that thorn, showing how the grass sword is able to guide him through the toughest times and help him bring everything back to normal. But there’s really no telling what will happen, especially when Finn’s dad is still somewhere out there.