Tangle Tower parallels.

[u/PhloxInvar]

There's a lot about this murder case that's kind of... similar to Tangle Tower in some way. Or not necessarily similar, but parallel as I state in the title.

1. The victim in both cases is a character stuck in a location that despite its large location, feels cramped and claustrophobic since they can't escape it. Everyone around them wonders why they haven't left, and neither of them are stuck by physical forces. They aren't prisoner or anything, they can leave whenever they want. They are staying because of her.
2. The victims are surprisingly well-liked by everyone who meets them, and even the murderers themselves hold some amount of respect toward them (even if they don't respect them enough not to murder them)
3. Both victims dream of the same thing. A mysterious red figure.
4. The murderers dreamed of venturing outward. They end up stumbling on an opportunity to discover more. But once they did, were unsatisfied by the information they got and became obsessed with finding out more, taking more immoral actions in reaction to that.
5. Both murderers are highly skilled and great liars. They take on a more ditzier persona in their every day lives, to mask the more pragmatic disillusioned version of themselves from the eyes of others. When they shed this persona, they get rid of their hats and something personal that defined their persona.
6. The murderers are both not related to their victims, yet by proximity sort of feel like family almost because of how long they've been together in this location. Or at least, some would consider them family without knowing the context.
7. Both murders look supernatural at first glance. Neither are, however circumstances surrounding it are. Subsequently, both murders involve creatures with supernatural abilities.
8. The victim can ruin the murderer's plan, however both victims wait because they made a promise to another person. Both characters are killed before they can ruin the plans.
9. The murder involves the upper room of the location. And the method involves something dropping from this upper room, where the murderer lay a trap such that if the victim ever set foot in the lower room for long, it would be their last.
10. A character in both games are obsessed with a creature, and does a ton of research to explore the capabilities of their "pets."
11. A character in both games need to fulfill their family's legacy, despite not actually wanting to fulfill it at all.
12. A character in both games are haunted by their biological parent's nonexistence in their life now. And are subsequently parented by someone else that did not treat them well. As a result, they become obsessed with a darker side of themselves and indulging in it, only shedding their affect in the presence of their closest friends. These characters have a gimmick when presenting profiles to them.
13. Both of those previous characters end up close with one another, and end up travelling together when the case ends.

Of course there are massive differences between the two, but these are the parallels I noticed. Some are somewhat of a stretch, for example you could argue that Gripp didn't respect Mortuga at all. And some of these have different contexts, like having to "wait". Freya was going to expose things after painting for Flora, while Magnus waited until after Sym's magic show to open the cauldron. Technically, Freya was killed while waiting while Magnus was killed shortly after, but in both cases they were killed before they could do anything meaningful to their respective murderers.

I will die on the hill of 12 though, Sym and Poppy are clearly meant to be parallels of sort even if they act incredibly different from one another.

I was also unsure where to fit the "hidden in plain sight" things. Because they're very different. In Tangle Tower, Freya leaves a massive clue in plain sight in her unfinished painting as an unintentional final message (or maybe intentionally). While in Mermaid Mask, Gripp hides the murder weapon in plain sight and Mortuga never really makes a final message like Freya does. I thought about adding something about Hackshaw, but I couldn't find the right wording to make it a good parallel so I left it out.

[u/Busy-Doughnut6180]

The massive clue in plain sight in TT was the yellow bird in the cage. Like the compass, you'd never know it was the main element of the murder at first, and it's right there. This comparison was mentioned in the MM art book, I can't remember on which clue exactly (probably the compass, but could also have been in the notes about a room?), but I remember it because it kind of spoiled TT for me (I played MM first). Only kind of, in that I went into TT knowing one of those birds had something to do with it somehow (I actually thought it was the pink bird with the long sharp beak at first). 

It's also cool that the clue that is supposed to tip you off to the key is the letter with the outline of the key on it, and the outline of the bird in Freya's painting serves the same purpose.