Magic

Magic is the energy used by Magical Kids and Magical Creatures alike, as their names suggest. It can be used to craft weapons, summon weather changes, change temperatures in wide or short ranges, feed Agreemen, increase the user's strength, and many other things.

How It Works
Magic is a form of energy, generated by the body much like Heat. While it doesn't have many special properties on its own, it can be transformed into any other energy type. For example, controlling your magical energy to create a fireball is simply shifting a small amount of energy from Magical to Thermal. Creating weapons, on the other hand, is using the energy to move and change atoms, even changing the amount of protons, neutrons and/or electrons if needed. Magic is produced by the whole body, but is mostly accumulated around the heart.

How It's Used
Magical Kids use their magic by finding it deep inside themselves and making the decision to control it. It's often described as "trying to blow something up with your mind, but with your heart instead", as that's generally the feeling received when using magic.

It's unclear how monsters use magic, as they have no heart and some don't even have a real body. It seems to depend on the monster.

Agreemen can use magic in much the same way that Magical Kids do, but are more likely to simple absorb it, similar to a plant absorbing sunlight, as food. Most agreemen agree that magic is tasty stuff.