Mono

The Icarus figure, driven to insane heights by ambition and recklessness. His suspension train with rails made like rollercoasters is called His Highness because he has an unfortunate love for puns

Like listen bro... Train conductor, but make it aerial... Make 'em the mad scientist trope except mad conductor/engineer! Too ambitious!! Take risks for the sake of having a cool flying train!! Drives at extreme and dangerous speeds!!!

Theme Song 

He’s form-shifting as well. On ground level, at his usual and in his white dove form, he's rather sickly but disguises it as normal. He's hospitable, polite and pleasant, always with a kind smile on. It's useful for when he needs to get his projects approved by the city council. He drives experimental public transports, after all. But the truth of it is that it’s rather a subdued version of his energetic self, weighed down by his chronic fatigue making him sluggish.
As he gains altitude and the monorail starts up, his spikes come out, contrasting against his skin like black feathers. Wings of spikes sprout out of his back, and his long hair loses its updo with the hectic speed and the black underside flows behind him. He becomes the magpie.

So he’s like a whole different person in and out his monorail. He’s very professional and cool-headed and always has a polite soft friendly smile on when he’s inviting you to board on a monorail station, but he steps in and gets the cart moving and suddenly it’s no more "May all passengers find their seats, we depart in 2 minutes~" it’s "ARRIVAL AT DESTINATION IN 30 SECONDS, PROTECT YOUR SPINE AND BUCKLE IN HAHAHAHAHA"

So he’s a blobfish right, and his whole thing is being overtly hyped and obsessed about his flying train thing… The thing with blobfish is that their infamous appearance is a deformed version of their actual, healthy appearance. They’re a deep sea fish, spiky and pretty normal looking, but getting fished and reeled up through the sea level pressure quickly makes them kind of implode and melt, so they arrive to the surface a pink saggy bad of flesh… Cue Mono’s peculiarities:

Mono is from a community of blobfish sea terrors, and they have a tabboo about even attempting to go to the surface, because it’s dangerous and all. Mono was really set on going to the surface though, he’s pretty idealistic and his main interest is inventions and new discoveries. He wants to see the world, create great things! So he goes to the surface. His body… Does not adapt well, but he does survive. That’s where his skin/shell’s stitches come from, a medical surgery. But on land, he still looks like that more deformed version; somewhat bloated with only his fins showing in his mimic: a white dove.
But then- he discovered trains. They go at high speed and revolutionized the transport industry and engineering. But then? Sky trains, ones that aren’t as well researched or optimized, and that’s when he chooses that he’ll dedicate himself to try and create the most performant, best aerial monorail possible.
The truly great thing about being a train conductor though, is that the quick acceleration as the train speeds up and moves through atmospheric pressure and altotude is that he can get back to his state as if he was in deep sea with both his fins and spikes out, aka his magpie form, and that’s when the spikes of his crow mimic come out, and why he feels so energetic and gleeful, and well, frankly manic. He feels great for an instant every time he accelerates and goes at incredible speeds or going up and down like a rollercoaster! That’s what makes the passenger experience scary and terrible though, while he’s having a great time lol. His aerial monorail train, "His Highness", is everything to him.
The experimentation and lot of atmospheric changes at high speed does strain on his body though, and if he does it too much in a day he starts coughing up blood.

Beyond even just discovery and revolutionary engineering though, his ultimate motivation is to eventually be able to make a monorail that can go underwater straight into deep sea, and keep the ride up to the surface safe for other blobfish sea terrors, even through the intense atmospheric pressure change. It’s a pipe dream mostly, pun intended, but it’s close to his heart. And he hopes to one day be able to go back and prove to them that he was able to do it, and that they could do it too. He‘s just definitely pushing himself into an early grave as he works on that.
So ya, big theme on disability and limits and unhealthy ambitions, but also like… He does bring monorail engineering to a more advanced stage and all even if it isn’t perfect y’know so pick your poison. Health or ambitions?

-Mono shifting from dove to magpie-
"?? What was that?? What are you??"
"What? Oh I’m an hybrid, my dad was a crow and my mom a dove, so I'm a mix of the two aka a magpie except I can also shapeshift from one to the other"
"That’s.... Not how biology works"
"-sweats in eldritch creature- it... isn’t....?" -cue them putting the train speed at max to escape conversation-

Fun local history tidbit: