+Anima

The plot revolves around four +Anima children: Cooro, Husky, Senri, and Nana. Brought together by their +Anima powers, they search for others like themselves and a place to belong. Along the way, they encounter villains and friends alike, as well as other +Anima.

In the +Anima fantasy world, some humans have an unusual gift that grants them the ability to morph one or more of their body parts, such as limbs, into a form similar to an animal's body part. Some are capable of even more radical changes, such as growing wings or full-body transformation. The transformation processes are very fast, and occur at the user's will. When inactive, the morphed areas revert back to normal, leaving the person's clothing and body completely untouched. The only visual mark of this ability appears on the body of the person, in the form of a black tattoo-like marking. Occasionally, the user bears some behavioral characteristics of their animal, but this is not very common.+Anima are not treated kindly by the normal humans. Therefore, when some are treated bad enough or have a taken over neglected feeling, their Anima often takes over them.

All who have such an ability are collectively referred to as +Anima. The +Anima are capable of controlling their powers at will. Their abilities range widely — including, but not limited to, superhuman strength, agility, and reflexes, as well as heightened senses, and the growth of physical features such as fur,claws or wings. All of these originate from the characteristics of a +Anima's animal. Every +Anima bears the characteristics of only a single animal. Some who have been experimented contain two or more +Anima, each alone, or the two or more +Anima might fuse together to create a different or whole new +Anima. These experiments make the user's body a permanent animal trait such as a tail and claws pop out of the user when they are angry, embarrassed, or scared.

The origin of this phenomenon is rumored to come from the Kim-Un-Kur, a type of Indian tribe(s). the criteria for one to become a +Anima is being slowly revealed. The main one of which are; 1) They are usually children age 5-14, they are very close to death or in a desperate situation. The Kim-Un-Kur seem to break these criteria, as they seem to voluntarily equip their +Anima and do not seem to vanish under the criteria under special experiments.

There are different theories how an animal is chosen for a +Anima. It is also possible for +Anima to be implanted into someone or the person done experiments on. Lyra was originally a normal human, but had said she was implanted with her recently disappeared swallow +Anima by Fly Greena Aight, a royal researcher in Asteria. In other words, naturally given +Anima are like birthmarks - they are more permanent and bestowed to them naturally. An implanted +Anima is not like the real thing and can fade over time.

The +Anima's powers are not understood by the normal people, and the +Anima are subject to negative prejudice. Similar to the X-Men of Marvel Comics, they are feared as monsters, and even hated by some. Some are envious of such powers and seek to gain control over them. Thus, afraid of the negative reaction from others, most +Anima tend to hide their true powers whenever possible, although Cooro doesn't seem as ashamed of his powers as the others. He actually tends to love, cherish, and show off his +Anima powers.

The treatment of +Anima differs greatly in Astaria and Sailand, the two major countries in the +Anima world.In Asteria, +Anima are treated in various ways. More commonly they are treated with suspicion or dislike, not necessarily hate, although some in the army see them as enemies. On the other hand, +Anima are valuable slaves, for example; Crystala (Husky's aunt, the twin sister of the king of Sailand) buying Senri for 7000 gillah (1 gillah = 100 pillah, 1 pillah = 1 yen). They are looked down on and seen as less than humans. They work for their masters and are arrested by hunters and sold in slave markets if they have no master (which happened to Husky at one point). To identify them as slaves, they are forced to wear collar- like chokers with their masters symbol.

Another reason +Anima can be considered outcasts and dangerous is the fact that their +Anima can get stronger over continuous use for daily life, even to the point where individuals eventually (most likely involuntarily) give up their human sanity and become more and more like the animal they were bestowed.

There is also indication that they it may be possible for them to lose their powers, such as the blacksmith's wife.