Mermaid Adrian Headcanons:
A good 60 foot long with shimmering green tail that is most of his length. his body and tail is covered in dark markings that dimly glow in the dark
He straps kelp to his tail so he can blend in even with his tail exposed.
He still bares human features but his hand and forearms are covered in rough scales for him to eat urchins and other poisonous fauna.
Note: he is immune to most poisons. Meaning he can eat/handle most fish.
His mouth looks human but hides a mouth that opens wider than a normal humans and is full of razor sharp teeth, perfect for swallowing things whole.
His eyes are mostly blacked out with his pupil to allow him to see in the dark.
His ears are less ears and more fins to allow him to hear and detect changes in the water.
Two sets of gills one on his neck and the other by his hips.
He has dorsal fins on his back that he can flare out to seem bigger than he actually is and can be used for speed in the open ocean.
Adrian lives in a cave that’s surrounded by a dense kelp forest that keeps him safe and hidden away.
He is very wary of humans and watch them out of fascination.
his cave is full of things he has taken from the bodies of humans or from boats left abandoned or unwatched.
He just has a stack of water logged books that he can’t read but likes to look at. Along with many other things scattered though his cave.
He can speak broken english kinda of like a small child. If he does he will often click and chirp though they don’t mean much in his language but they are from the stress of speaking another language and above water.
When he sleeps he curls up in his cave around a rock.
his species of mermaid has their childern and raises them for a while then leaves them some where safe. returning every few days to watch them and make sure they are learning how to tend to themselves.
He does have mermaid magic. A kiss from will allow a human to breath underwater and will grow human legs if he is taken a certain distance on dry land.
Theses below are taken from @rainveined‘s mermaid headcanons with permission and they are the person I plotted this au with.
Courtship and mating: (cannibalism tw)
Mermaids Bite their chosen mates, leaving a permanent mark on them. Meaning that biting is a big thing for him.
The bites are often very sensitive, serving as both engorge nous zones and marks of being paired off.
Mermaids mate for life, and will ‘imprint’ upon whoever they choose. Imprinting is often mutual, save for the extremely rare cases of human/mermaid relations.
They also like singing to their mates as well as both part of comforting them and courting them
Mermaids are highly protective of their mates, especially during mating season. This also extends to them protecting their personal territory.
Mermaids give live birth like some species of sharks. Offspring are fully developed at birth, including teeth, and are capable of swimming on their own, though parents will keep their young close.
In the womb there are two zygotes pretty much 95% of the time. The reason there are two zygotes, but only one is born, is that one typically eats the other before birth.
Essentially one twin becomes a way of ensuring that the other is well fed, has enough nutrients, and is healthy when born.
It’s often that pairs will twine tails when together and lax.
Mermaids can often change sexes or become hermaphrodites to become fertile and produce offspring. Often that means that while they’ll have one set of fully developed genitalia, they will have a set of half developed as well, in case they need to change to become compatible with their mate.