Star vs. The Forces of Evil has been a popular and well-loved series right from the start. With the quirky cast and fantastic humor, this isn’t terribly surprising. Naturally any series that can cultivate its own fandom also has its fair share of fan theories as well.

In the case of Star vs. the Forces of Evil, there are countless fan theories floating around out there. There are however, a core set of theories that keep popping up again and again. Here are some of the more interesting ones floating around out there.

10. Marco Diaz Is Not As Human As He Appears

There are two different theories pertaining to Marco’s possible lack of humanity here. The first theory is that Marco is in fact, Mewman, Either part Mewman or full that is somewhat more open-ended.

With the release of Star’s Book of Spells, there are a whole lot more reasons to believe that this may actually be possible. There are also multiple hints here and there to support the theory. For example, Marco’s ability to hold and use what was Star’s wand. He shouldn’t have been able to do that. Another supporting theory is the fact that crescent moons appear on Marco’s cheeks from time to time. Sound familiar?

There are two branches of opinion in this theory. The first is that Marco is the descendant of a commoner. A Mewman still, but a commoner nonetheless. The other theory is determined that Marco is actually a descendant of Eclipsa herself, or perhaps Solaria (both have theories here). This would mean that Marco technically could be considered the rightful heir to the Mewman throne.

9. Marco Diaz Isn’t Human or Mewman

This theory has less traction than the first, but it’s still worth talking about. There was some foreshadowing for this theory earlier on in the series, but with the appearance and explanation of Eclipsa it has dawned a little bit.

The theory posits that Marco is actually part monster. It could be that he was born that way, like Miss Heinous was. The other theory…is that Star’s magic changed him. Remember when she tried to fix his broken arm, and instead gave him a monster arm? That arm affected him more than just giving him a monster limb. It took over his way of thought, for a time. What if Star didn’t properly remove the limb? This would, in theory, mean that Marco has some monster in him.

8. Marco Diaz Jr. Is Going to Have Crescent Moons On His Cheeks

We’ve seen Marco Diaz – the original one that is – with crescent moons on his cheeks a couple of different times by now. The first notable appearance was when he used Star’s wand. But it has snuck up again and again since then. In the images of Star and Marc from the photo booth, you can see the moons on his cheeks in the bottom picture.

The question is, is this because of his constant contact with magic? Thanks to being around Star so much? Or is it genetic? Marco Diaz Jr. should be able to provide us with some answers here. If the theories about Marco being Mewman are correct, his little brother should be born with the crescent moons (or another equivalent symbol) on his cheeks. We can’t rule out Star’s influence here, but consider how little time she has spent with Marco’s mother lately, it seems unlikely.

7. Toffee And Eclipsa

Like always, there are a couple of different theories on this count. Some fans are convinced that Toffee is related to Eclipsa – after all, just because she had one child she acknowledges, doesn’t automatically mean that she didn’t have any others. Or that Miss Heinous didn’t have children.

The other theory is that Eclipsa and Toffee were quite possibly a thing, once upon a time. Naturally we can assume that this was before Eclipsa met her husband. In Eclipsa’s chapters of the books, we see that she actually has a rating system for monsters. And no, it isn’t a rating system for how easy they are to kill. It’s to rate how attractive they are. One of these monsters looks an awful lot like Toffee, and describes him as looking good in a suit…sound familiar? It’s all conjecture of course, but isn’t that all we’re doing?

6. Intentionally Ambiguous

This theory may seem minor, but the implications could be huge. The theory posits that the difference between monsters and demons is intentionally ambiguous. This is likely to help reduce how obvious the double standard actually is.

Star’s family has an alliance with the demons, and she even dated Tom, a demon himself (or half demon). Yet her entire family, with the exception of Eclipsa and Star, viewed monsters as evil and worthy of declaring war against. But what is the difference between the two? Couldn’t and shouldn’t demons be considered a subset of monsters? Is it simply because they have a thrown, power, and money that they’re tolerated? Because the demons are certainly looked down up, just not to the same level as the monsters. The double standard is jarring, especially the more you think about it. It leaves us to believe that they were intentionally hiding the differences between the two, because they didn’t want their people to think about it too much.

5. Toffee the Killer

So, none of us were in any doubt about Toffee’s ability or willingness to kill, right? Good. The theory posits that Toffee killed both Queen Comet (Moon’s mother), and Queen Solaria. We already know that Toffee killed Queen Comet. Even if he wasn’t the one that directly did it (which is unlikely) he certainly ordered it.

When he killed Queen Comet, he added a skull on his shoulder with diamonds on the cheek. Just like Queen Comet once had. Toffee also has a second skull on his other shoulder – one with clubs on the cheeks. It feels safe to assume that he killed another queen in his time. Some fans think that he killed Solaria as well. There has been some proof that he was around in her time (Eclipsa may have written about him in her chapters, as you recall). The one problem with this theory is that Queen Solaria is portrayed with lightning bolts on her cheeks.

It’s possible that he opted to go with the clubs as some sort of message to Eclipsa. Perhaps it’s in support of her, or as a warning. We don’t know enough to be sure, yet. It’s also possible that he killed a queen with this symbol on her cheeks, and we just don’t know which one.

The only part that isn’t in question is Toffee’s willingness to kill multiple queens. He would have cut through anyone needed in order to get what he wanted.

4. Glossaryck Actually Knows What He Is Doing

What are the odds that Glossaryck actually knew what he was doing the whole time? And that he's just really good at playing dumb? Glossaryck has done a lot of things that appear stupid or stubborn at first, but later prove to actually show intent behind them. At least, according to him. Such as hiding in a donut box, or forcing Star to gain better control in order to keep Marco out of her diary.

During the Bon Bon the Clown episode, Glossaryck asked for permission to burn one of the pages of the book, for ‘warmth.’ Even though he is a magical being, and wouldn’t need to burn something to warm himself up…in theory at least. The page he burned had a rat on it, and he was shortly kidnapped by none other than Ludo and his rats. Coincidence? It’s unlikely. The theory is that there was a spell on that page that Glossaryck did not want Ludo, or Toffee, to get their hands on.

3. This Was All Eclipsa’s Plan

This is one of those theories that is hotly disputed among the fans. Some believe that Eclipsa truly is a victim, judged only for her willingness to accept and love monsters. Others believe that she’s an opportunist at best, and a schemer at worst.

Regardless of how you’re willing to look at it, the truth is that Eclipsa did take advantage of the situation at hand. Nobody seemed to get hurt though, so take what you will from that. She did get everything she wanted in the end; the wand, her daughter, and her husband. Though let’s be honest here, the latter two are clearly more important to her than the wand.

2. Globgor Is the Antagonist Everyone is Unprepared For

If we’re going to judge based on looks alone, then it’s probably safe to say that Globgor is a terrifying monster. He’s huge, presumably strong, and his family has recently been threatened. Not to mention the fact that he’s been forcibly crystalized for years (as was his wife – a fact that he will likely not be happy about).

One hint in the favor of Globgor being a problem? Remember that silly word that Glossaryck kept repeating? That’s right! Globgor. Was this a warning, or is something else going on? Either way it doesn’t bode well to the reappearance of Globgor.

Another concerning factor: Globgor clearly has authority over the other monsters. Remember, the temple that Toffee/Ludo hid away in? That was Globgor’s. He was even called the king of monsters. How large of a monster force do you think he could gather, if he put his mind to it?

1. Marco…Turns Evil?

This isn’t exactly a theory that anyone wants to consider, but it has to be done. What if Marco turns evil? There has been plenty of foreshadowing that something is going to happen between Star and Marco.

Most fans would like to believe that it’ll be something positive – especially the Starco shippers out there.

But what if Marco and Star end up on opposite sides? We’ve had a few indications now that Marco isn’t human, and moreover, we’ve seen some concerning signs as well. The way the wand looked when he held it, for example. There’s a lot wrong with this one. For one thing, it simply looks sinister. For another, the bat wings on the wand are eerily similar to the batwing jutting off of the ‘Evil’ in the Star vs. the Forces of Evil title.

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Even if this theory is correct, it doesn’t automatically mean that Marco has gone bad on us. Plenty of people do bad things for good reasons. Marco has a good heart, but he’s also easily swayed. Somebody like Eclipsa could believably manipulate him here.