‘Demon Slayer’: What Is the Blue Spider Lily & Why Is It So Important to Muzan?

Muzan Kibutsuji is the main antagonist of Demon Slayer. He is a Demon, being the first of his kind, who has lived for more than a thousand years, being as such, the one responsible for the origin of the other demons, responsible for having corrupted Michikatsu Tsukiguni and being the one who murdered Tanjirō’s family and Nezuko, turning the latter into a Demon, being the trigger for Tanjirō’s desire for revenge towards him. In this article, we will talk about one aspect of Muzan’s story, and a very important one at that, as you will find out what the Blue Spider Lily is and why it is so important to the Demon King.

The Blue Spider Lily is a mythical flower that is said to grow for only a couple of days a year, during the day and under certain conditions. It has some exceptionally powerful supernatural properties and can be used as medicine. This flower saved Muzan’s life when he was young but also turned him into a Demon. It is said that it can eliminate a Demon’s weakness to sunlight, so Muzan is looking for it.

The article will elaborate on the answer we have provided you with above. We are going to tell you about the Blue Spider Lily, as well as why Muzan is so eager to find it. You’ll also find out how exactly Muzan’s history is connected to all of this and what role in the story the Blue Spider Lily has in general. The article is going to contain a lot of spoilers, so be careful how you approach it.

Muzan survived thanks to a Blue Spider Lily, but he also became a Demon

The Blue Spider Lily is a powerful mythical flower from the Demon Slayer lore. It is said to look like a regular spider lily, but instead of the usual red color, it is actually blue. The flower is very difficult to obtain. It grows only in certain parts of the world, and due to its specific nature, the flower blooms for only two or three days a year and only during the day. After that, it closes up again and looks like a large horsetail weed, but it is useless in that state. Also, based on the atmospheric and geographical conditions, it might never bloom at all. This is why it is so difficult to find and why it has such an important status in the story.

We know that Muzan Kibutsuji and his Demons vehemently look for the flower. But how is it actually connected to Muzan? Well, to answer that question, we have to go back in history. Way back, actually, to when Muzan, the original human, was born.

While Muzan was still in his mother’s womb, his heart stopped numerous times. Since the child was born without a pulse and did not breathe, they declared him stillborn. Yet the first time he cried out was when he was brought to be cremated. He was diagnosed when he was young with a condition that would cause him to pass away before he turned 20. The attending physician gave the specific prototype medication Muzan appeared to have no effect. Muzan murdered his doctor because he was furious at him over his deteriorating health. He didn’t realize the medicine truly worked and had given him a powerful physique until after he had slain the doctor.

And while all of this might seem unrelated, we have to stress that the prototype medicine given to Muzan by his doctor actually contained the Blue Spider Lily, although the exact recipe was never revealed; it was confirmed, though, that the medicine was exceptionally difficult to replicate, which is why no one has been able to do it since then. Muzan was aware that the Blue Spider Lily, thus, saved his life, but also cursed him because it gave him enormous, superhuman powers, but it also took away his ability to live as a normal human during the day, as he was not weak to sunlight, which would destroy him after enough exposure.

After a while, Muzan became aware of the Blue Spider Lily’s amazing attributes, and he began a search for it. Still, finding out that the Blue Spider Lily is very hard to obtain, he realized that he would not be able to do it so easily. This is the whole gist of his endeavor. Namely, Muzan Kibutsuji is an immortal and invincible demon. Under the right conditions, he could live forever, and there is no doubt about that. But still, a man who had almost everything went on a frenzied search for a flower that saved his life and cursed him simultaneously, believing that it could help him again if done right. In our next section, we are going to explain the importance of the Blue Spider Lily for Muzan and his plans in the series.

The Blue Spider Lily could make Muzan invincible

As we have stated, the Blue Spider Lily is a very powerful plant. It helped Muzan survive, but it also turned him into a Demon. And while it did grant him some amazing powers, it made him weak to sunlight, which is why all Demons operate only during the night. But, Muzan has also been told that the Blue Spider Lily could make him invincible. Namely, by consuming the Blue Spider Lily once more, Muzan could become immune to sunlight, making him invincible. This is why he is searching for it so vehemently, but this is also why he cannot find it. Knowing that the Blue Spider Lily appears only under certain conditions, Muzan cannot find it because he cannot take it during daylight. And that is the whole irony of his endeavor and why it is, at the same time, both dangerous and pointless.

But, after the Swordsmith Village Arc, Muzan was able to replace the flower

And while the blue spider lily was, as we know by now, presented as the only thing that could actually heal Muzan’s weakness to sunlight, most people would think that Muzan had no alternative whatsoever there, but they would be wrong. In order to understand that, we have to go back to the end of the Swordsmith Village Arc. Also, we have to reiterate that one reason why Muzan created so many demons, aside from finding the flower and eliminating his enemies, was because he had hoped that one of them would be resistant to sunlight, so he could simply consume them and become resistant (i.e., immortal) himself.

And while Muzan was waiting for around a millennium for such a demon, even losing hope that it was possible, a miracle actually happened. While he was, disguised as Toshikuni, looking for information on the flower, a dying Hantengu was able to send news that Nezuko was able to survive in the sunlight. He was thrilled and excited to hear this, as it meant that the blue spider lily was not necessary for him anymore and that he would be able to become immortal even without the flower.

Muzan started to revert back to his original demon form, happy, overjoyed, in fact, with the job Hantengu had done providing him with the information about Nezuko’s ability. He also killed his “mother” and the maid of the house then, but that is a wholly different story. Yes, Muzan was excited because he had finally found a way to become immortal. With Nezuko being able to “conquer the Sun” on her own, all that needed to be done was for Muzan to eat Nezuko, and he would, himself, also become resistant and, with that – immortal. He decided to focus all of his actions on finding Nezuko and eating her, but luckily, he failed in that endeavor and was ultimately defeated.

It is sheer luck that Muzan was unable to find the blue spider lily due to its specific attributes

As we’ve said, the blue spider lily flower is very difficult to obtain (spider lilies are usually red in color, and they don’t appear in blue in real life, which is why it is so symbolic for the story). It grows only in certain parts of the world, and due to its specific nature, the flower blooms for only two or three days a year and only during the day. After that, it closes up again and looks like a large horsetail weed, but it is useless in that state. Also, based on the atmospheric and geographical conditions, it might never bloom at all. This is why it is so difficult to find and why it has such an important status in the story.

How was Muzan, with all his resources and the time he had, unable to find it? You could probably find anything if given a thousand years to do so, but Muzan was still unable to get his hands on the flower, which is why he was so happy to hear about Nezuko’s ability, as we’ve explained above. So, back to Muzan and his failure.

As far as the location is concerned, Muzan probably could have been able to locate a spot where the flower bloomed. The records were scarce, but he had so much time on his hands and so many demons as well that he probably could have, at one point or another found the flower he was looking for. He would have to find them during the short period that they bloomed, but that would also not be a problem for him. Given his abilities, he could simply sit next to the flowers for a year until they bloomed and then harvest them.

But, there was a major issue – the flowers only bloomed during the day. When night would fall, they would revert back to their usual form and would be completely useless to Muzan. And that is the main reason why Muzan was unable to harvest these flowers. As he was weak to sunlight, he would actually die while waiting for the flowers to bloom so even if he had found them, he would have been unable to harvest them during the day.