1. I think Sly would enjoy jazz.

2. There are two types of maggots in Hallownest, ones who turn into flies, and ones who are perpetually maggots (Or only female maggots metamorphosize, like Grubs), which means once forced to do menial labour like the other maggots as well, at least before he escaped.

3. Along with the idea that maybe only female flies metaphorize, Sly is trans masc.

4. Esmy was Sly's older sister, and they didn't really interact all that much till they helped each other escape Hallownest, and only then did they start to become friends.

5. All flies being short factoid is actually a statistical error, Sly Georg, who is 10,000 feet shorter then every fly and maggot in Hallownest, is an outlier and shout not have been counted.

6. Sly was kind of a jerk before he became a Nailsage, and along with that, I like to think he has NPD.

7. Sly also has ADHD.

8. Even before becoming a Nailmaster, he already knew a bit on how to wield a nail from trial and error.

9. Sly is somewhere on the objectum spectrum. I can sense it.

10. Whenever Sly is content or really happy, he starts buzzing, which his adopted nailmaster children ended up adopting as a habit.

11. Sly had always been greedy, originally out of necessity, and now as something that just stuck.

12. Sly probably would've been a Nailsage till death if it wasn't for gaining chronic pain from constantly wielding a great nail three times his own height. He made sure he lasted till he had to see his children away for nailmastery.

13. Even after having to abandon the nail arts for being a merchant, he still makes sure to sharpen and clean his nail every morning before opening up shop. (See #9.)

14. Heavily dislikes both the Pale King and the White Lady.

15. During his time as a nailsage, he would hold classes for the Nail arts.

16. As you might suspect, it is hard to become a nail master, and even harder to become a nailsage. After Sly's own master's death, he was the only Great Nailsage in Hallownest and its surroundings. His children are the only Nailmasters, despite how many people he trained

17. Not really a headcanon, but he was a great father towards his adopted children.

18. Sly doesn't really have a clear idea of whether or not Esmy died, as she seemed to just disappear. To him at least, it's safe to say she's dead, which is better than falsely hoping she might be alive.

19. Out of pure boredom during the times there aren't a lot of potential customers, he sometimes talks to the nails he has on his walls, or when he closes shop, his Great Nail.

20. He has a really good sense of what things are around him or moving at all times.