MERPERSON TRAITS:
— Out of water: Fins on their legs (or frog-like legs) and webbing between their toes.
— Bioluminescent spots or patterns on any part of the body.
— Gills on the side of their neck, although they are still capable of breathing outside of water.
— Scales on their arms and legs that can come in a wide variety of colors and patterns.
— Fins behind their ears and on their forearms.
— Reacting to water: Their legs will form a tail that can be any length and resemble pretty much any aquatic creature (things like squids, frogs, and octopi are fair game for this as well).
— Drains water from victims by making a cut on a part of their body and then leeching the water out.
— A “soothing” singing voice that can charm humans, making them vulnerable to being lured. (we all know that eren either chants or screeches)
— An instinct to hoard any sort of gem or other shiny trinket underwater, and to act extremely aggressively towards thieves.
—Sharpened senses, especially underwater.
— A need for water.
—newfound obsessive love for music along the lines of sirens, a desire to lead people to watery areas, and secrecy.

SLIME TRAITS
—Faulty memory. Slimes are scatterbrained and have trouble holding onto short-term information.
—Poisonous exterior. We don't recommend licking Slimes, as their outermost mucus can inflict paralysis or nerve pain in the victim. (we’re going with a similarity to kaiju blue)
—slippery moral mentality, being "slippery" or cagey in regards to their feelings, and feeling a need to consume and/or absorb something in particular or everything in a katamari sort of way.