Merfolk

Merfolk are the general term for humanoids that inhabit the oceans and swamps while sharing some physical similarities to sea-life and semi-aquatic creatures. Most Merfolk follow the standard humanoid form which means to have the following: opposable anterior forelimb-appendages (i.e. thumbs), visible spectrum-binocular vision (i.e. two eyes) or biomechanic plantigrade-bipedalism (i.e. the ability to walk on heels and metatarsals in an upright position). Merfolk are also known to exhibit specific features of aquatic or semi-aquatic life, such as gills, fins, webbed hands and or feet, and typically have different colored skin compared to land life. However some Merfolk have been observed to have more aquatic qualities, such as not having legs, instead having a tail of a fish, where the legs would usually be.

Etymology
Stories of Merfolk have been spread across the land over hundreds of years, spanning different cultures and empires across the world. "Mer-" in Merfolk comes from a old human dialect, a derivative of the word "Mere" which meant "Sea". Folk, is self explanatory, referring to sapient people in general. The term "Mermen" and "Mermaid" can also be used interchangeably with Merfolk, but refers to a specific sex of Merfolk and is uncommonly used in contemporary society, in favor for the more general term of Merfolk.

Evolution
The evolutionary tree of Merfolk is poorly understood, compounded be the low amount of currently known existing Merfolk, no definitive timeline can be given. Researchers suggest the Merfolk are a subgroup of humans that chose to live in or around bodies of water, and eventually adopt more and more qualities of sea life through a combination of evolution and random genetic mutations. Religious officials meanwhile, suggest that Merfolk come from either a curse put by wrathful Gods as a punishment for disobedient mortals

Appearance
Merfolk are very diverse and their appearance depends on their environment & living conditions, but most of them share some key features.

Gills: they help them breath underwater in a more efficient way. they can come as small cut like holes on the neck or as big ears on the side of their faces