Yokai are creatures that consist of : spirits, monsters, undead, demons, and other such creatures which would not be considered that of the living realm. The most common mark on a Yokai is a black diamond shape.
The Akuma no Box is a demon which is a portal object. If you open it's back, you can get to any dimension/place desired. Technically, you could even go back in time using it. However, it does not open unless you give the password. ^^' It is also a very stationary demon, and can withstand any attack. The only way to rid of it is for it's master/creator to say a particular Sutra. It's top speed : speed of light, however it does not move much. It is completely resistant to all elemental attacks.
The Bôs Demon? has incredible endurance and can withstand some rather hard punches. However, it's weak point is it's small limbs. It's top speed is 25 mph. It is resistant against melee attacks, and weakest against Rune attacks.
Demon Swans have the main body of aswan, and its eyes are those of a snake. It has talons instead of webbed feet, and it has a diamond mark on its neck. It can stretch its neck, and has rather sharp, venomous fangs. It can also fly, but it cannot fly far for long. Its top speed is 60 mph. It is weaker against the Earth and Fire elements. It is more powerful in watery environments.
The Diamond-back Serpent? can fly, and has great hearing and smelling abilities. Its drawback is that is color blind, and that it is physically weak. It's top speed is 150 mph, although it prefers 40 mph. It is weak against the Air element, and is strongest in watery regions and in the Earth.
Draconauts have the upper half of an elven child, and the lower half of a baby dragon. They also have the wings of a dragon. It can fly, breathe fire, and can resist any fire, thunder, lightning, and air attacks. Because it so small, it is also light. Because of this, it is rather fast. These creatures are rather rare actually. Top speed: 130 mph. It is strongest in the air, and is completely resistant against the Fire element, while it is somewhat weak to the water element.
An Enix can transform into anything, at the cost of the use of water. However, aside from that, it's pretty much useless. It's top speed is about 20 mph. It is extremely weak against the Fire element, and is most powerful when around water.
A Glüm is a needle-like demon that can levitate, and possess many objects at once. If it passes through a living creature, the creature becomes incredibly gloomy in personality for a few minutes. It's top speed is 38mph. It’s weakness is Rune attacks(“magic” attacks) in general.
The Gum is basically a rabbit-like demon that is incredibly fast and very heavy, resulting in very fast, and hard attacks. It fights like a boxer (hits with its ears, since they are much longer than its limbs). It's top speed is 200 mph, (although it prefers somewhere around 120). It is weak to the Water element.
The Isshis? demon is particularly slow. It's rather annoying, since it's got a smart-mouth, however, it's a telepath, and can be rather useful, but, when against it, it can be a rather mind-breaking foe. literally. It's top speed is 15 mph. It is weak against the Fire Element, and is strongest in around mountainous regions (it’s homeland), and in the air. It can suppress shaman’s powers because of its telepathy. This applies greatly against the Mage and Animist classes, as they rely on their powers of the elements the most. It’s weakness are Rune attacks (non-melee attacks; attacks which use chi/chakra).
A Kage is a shadow of a vengeful spirit which has lost its body and it can only live fully in other shadows. It's most powerful at night time, when it can control any object at will. Because it is a Shadow, it can manipulate other shadows, should it touch the shadows. Its top speed is 40 mph. It is weakest to the Fire element, because it is a great source of light, and can burn the Kage.
The Kagi? demon has the body of a dull key, with small arms out the long part of the body. It can transform to fit any lock, and is incredibly fast. It's top speed is 170 mph. It’s weakness is the Fire Element.
Lagoos look like little versions of Pikachu without a tail. It has a horn on their head, and a diamond on their chest. It can fly and its horn can be rather painful as it is one of the sharpest objects known. Its top speed is about 30 mph. Its weakness is Fire, Water, and Earth elements. It is strongest in the air, and is somewhat resistant to melee attacks. The Lagoos are generally friendly creatures however.
Margaux (said as Margo) is pretty much harmless. However, if you seriously piss it off, it'll shoot out a beam the strength of 100 cannons put together. Its top speed is about 60 mph. It is resistant against the Fire element, and is very weak to the Earth element.
The Onichou (Demon Butterfly) is known to be rather fast, and spits poisonous-glowing-neon-blue fire. Its top speed average is about 100 mph. Its weakness is the Water and Earth elements. They are more powerful in the air, as they are butterflies.
The Oniinu (Demon Dog) is known to be able to howl supersonic waves that make your ears hurt and/or fall asleep. It also bites rather painfully, and if not treated within 12 hours, the bitten could die, and become an Oniinu. It is not particularly fast, but its top speed average is around 60 mph. Its weakness is the Fire element. It is stronger in Marsh lands and beaches (Water-filled enviornments in general) because the sound waves they transmit are stronger there.
The Onineko (Demon Cat) is rather fast, and can camouflage like a Chameleon. Its skeletal structure excretes a miasma as a defense mechanism. When the miasma enters the body, it can degenerate the body. Its top speed is known to be around 100 mph. Its weakness is the Fire element. It is stronger in dry land, and is some-what resistant to the Earth element.
The Onionna (Demon Lady) look just like elven woman, except they have small horns on their head, and diamond marks on their hands and feet. They are much like Sirens of European tales, except that they must collect souls to live, and so to obtain them, when they sing, they attract souls out of the victim's bodies. They are rather slow creatures, and try not to go faster than 20 mph. They are especially weak to the Fire and Earth elements. They are more powerful in environments with high amounts of water.
Pixie Goblins have the wings of a pixie, and ears and wits of a Goblin. They look pretty much human aside from that, although their legs are brown, as well as their hands, and their upper half is tan. They also have the noses of cats. (:3). They can fly, and can absorb damage, and throw it back later on as pure energy. Their top speed is about 85 mph. They are strongest in the air, and are somewhat resistant to Aerial attacks. They are weakest to the Water element.
The Shi Shi Tago (Laughing Octopus) has the appearance that of a small Octopus which smiles, and has 6 small black diamonds around the bottom of its head. It can fly, and is immune to all water-like attacks, since it is, a type of octopus. It laughs like "ShiShiShiShi..", then squirts out a poisonous ink. It's top speed is about 75 mph. It’s weakness is the Fire Element.
The Skii is shaped like a lampshade, with legs and horns. It can possess any object at will, and can pass through anything. However, it is rather slow. Its top speed average is about 20 mph. Its weakness is the Earth element. It is more powerful in the air, and can resist the Fire element for long periods of time.