The following is a record from the Scholar Binder, Tobias Amberhorn
In the old tongues, majimonsters were originally known as dragons. In the old definition of the maji, a dragon was a natural beast infused with magic, making it faster and stronger, but enslaved to the maji's will. They experimented on any animals they could get their hands on, ranging from small fleas, leading to the creation of the electrically charged Statick and the mind bending Dibbiks, to whales and elephants, creating the ocean dwelling Kamuoy and Sludgaphants. Eventually, these maji then started to experiment with plants, natural phenomenon and disasters, objects, multiple types of aether and hybrids of animals stitched together by magic. Some famous examples of each of these cases include: Brushpyres, Cumulem, Batpack, Amphiboil and Chimystic, respectively. There have also been rumors of entire townships and locations being turned into monsters, but that is unknown.
Edit by Ranger Morag: Recent events have confirmed the existence of "kaiju", living city monsters, please see the record labeled: Kaiju, dwellers and you.
However, in recent years, new majimonster species beyond the original designs of the maji have begun popping up all over the Wildlands. The reason for this phenomenon? Inter-species breeding. Due to the original majimonsters being powered up animals, it's not impossible for them to begun mixing in the more mundane populations of animals and create new monsters. This observation was confirmed when a farmer named Albedo found an Amphare in his rabbit enclosure alongside several smaller rabbits and Amphares with similar fur patterns to it. Evidently, the aforementioned farmer ended up finding the Lapin Knight household, a noble binder family that specializes in rabbit monsters. We're not entirely sure how many other or new species of majimonsters exist in the Wildlands, but it is still comforting to know that all majimonsters can be considered some combination of the ten affinities: Fury, Ice, Lightning, Water, Wind, Earth, Fire, Basic, Mystic and Verdant. The less comforting fact is that most majimonsters are basically unkillable by human methods.
When the maji created the first dragons, they wanted perfect living weapons. Aside from infusing animals with magic to make them more powerful and have nature defying abilities, they also made them immune to man-made weapons. They are, however, vulnerable to phenomena such as gravity, lava, animals and old-fashioned pugilism, but it's usually considered a terrible idea to punch a porcupine made of glacial knives or a bear strong enough to eat boulders. The most effective means to fight a majimonster is with a majimonster, or a well placed bait into an active volcano.
It needs to be noted that when majimonsters die, they don't leave a corpse, instead they return to the aether from which they are made. In the case of bound monsters, they return to their drajules in order to recover, which takes about six hours give or take.