His tail is a bit dull at first due to OG park moondae being ostracised from other mermen so he's been just scraping by TT oh poor baby.

The tail regains its true golden sheen as both the bodyswapped Park Moondae and KSJ travel together ^^ idk if i translated well that he's a bit bony at this point. Just realised I forgot to render his body and neck gills. Oh well.

In my AU there would be all kinds of mermen. One thing to note though, they are BIG. as in long. Water snakes. I like thought of them being really long and strong.. Probably influenced by Rafayel's merman form lol.

For OG Park Moondae I imagine fins as being like betta fish tails.. Flowy and majestic. But his leans more towards being longer in length than spanning wide like in the ref photo. So a lot of his height is due to his tail.

In general a merman's main body is inherently vvv strong though, like a big snake. They're tough to cut through, and the strongest mermen are strong enough to strangle larger creatures with their tails alone. But to note, their gorgeous fins are on the delicate side, so it's a wonder that OG PMD managed to keep it wholly intact while surviving in the big blue alone.

Moondae, as he always is, quickly adapts to becoming a non-human pretty well. The not having feet is a bit nauseating sometimes, but he can appreciate the pros of having a tail. Of which is mainly for slapping KSJ when he's being annoying.

His teeth are sharper so at first when he meets the first human (KSJ) since he switched bodies, he talks a little slower to avoid biting off his own tongue by accident.

He mostly ate crabs and smaller fish when he realised he has to survive as a merman, but quickly upgrades to his signature yummy meals when he's able to get cooking amenities and actual seasoning from KSJ.

He's so sick of eating raw seafood that he doesn't care it's definitely suspicious how a merman knows how to cook. KSJ can make a pretty mean cocktail and every other alcoholic drink from his past experience as a crewmate, but his food is just okay.

KSJ has never eaten so well in his life, so he lets this matter slide.

-

I havent drawn in foreevr and never practised colouring + did this in like 20 mins. The tail gave me the most grief.. How do artists do that??

--- Start

Premise is Keun Sejin getting betrayed by his crew. He sails off solo with wanted posters Flynn Rider style (they cant get his gorgeous eyes OR his muscles right..) threatening his capture, so he's been island hopping to put distance between himself and his pursuers while investigating the crime he'd been framed for.

Queue one night he sees a streak of pink across the sky that disappears into the sea, and is commissioned to investigate by the fearful locals of the island he was moored at.

What he finds is unexpected. He meets an unaggressive and talkative unnamed fish man. He knows it's his target by the pink glow slowly settling in his skin and illuminating the water around them, the very same shade as the one that streaked through the sky. It was like a siren's call. That was the only explanation he could think of, seeing how the blush's shade softened the creature's features.

Do fish fly from the heavens nowadays? Angels typically came with wings, certainly not like the finned tail glimmering gold and resting across his boat, lightly draped and looping around him because 80% of the fish man is all wet, scaly, strong tail taking up space.

Back to topic. Right. The fish man has made himself at home in his boat. Because said fish man has decided Keun Sejin is to bring him along for his travels.

And Keun Sejin agrees, not because his brain stopped functioning at the dewey(?) eyes peering at him through wet wheat-coloured hair that clung to flushed(?) soft cheeks, but because he is a good man.

A Good Man who apparently is open to helping otherwordly creatures he's only ever heard about through his mother's bedtime stories as a child. His former crewmates might've flogged him for how little caution he'd displayed as soon as his eyes fell on his new fish friend.

When his brain finally catches up though, it quickly becomes clear that the fish man knew more than he let on. Strangely familiar with human culture, despite being a native of the sea.

And so they sail together, with Keun Sejin gripping his sanity by the skin of his teeth due to his unexpected passenger.

--- End

I love down bad Keun Sejin if it isnt obvious.. And it's fun to wonder what would Moondae do as a non-human being. Yes, he's brought to the world due to the System, but this time just like Cheongryeo he doesn't receive any hints on solving his predicament!

He is from the same world though, so he's not from the modern world and this isnt an isekai~ basically he went to bed and suddenly woke up in the ocean with a fishy body, and is suddenly approached by a young, strapping sailor! ^^