Magic in the realm of the MDU is vast. Each planet in the universe has its own storehouse or generation process to create and/or dissipate pure magical energies (an as yet energy that current science finds extremely difficult to sense or read).
Magical energies are generated by the extreme magnetic fields and the extreme churning of quantum forces, planetary core heat and solar/cosmic energy exposure. These factors coalesce into a dynamic power that has its own benefits and detractors. Some planetary cores have long since cooled and no longer generate their own magical energies (magically dead), however, planets like Earth are overflowing with magical energies. Earth, in fact, is noted in the MDUverse as being the 'richest and purest' magical source in the known universe, thus making it a target for others wishing to steal or siphon Earth's magical energies.
Over the centuries, man has learned to tap into Earth's magical field either through planetary saturation (from the earth, air, water, etc.), from fast moving lines of planetary magical flow (Ley lines), or from living (or even dead) beings that are imbued with fractional magical energies, like little magical batteries all over the planet. Utilizing a variety of methods (archaic, socially acceptable or morally irreprehensible), humans (and even some animals) channel Earth's magical energies through their minds and/or bodies (like a funnel or focus) and are able to manipulate the energies to a large variety of applications: shields, weapons, energy bolts, matter rearrangement, transportation (i.e., portals), and even control of others humans, animals or inanimate objects.
Training to detect, channel, focus, manipulate and control the magical energies of Earth (or any other magical source for that matter) takes an extraordinary amount of concentration and training. As such, nearly a dozen different schools of learning magic have cropped up on Earth, some as old as 10,000 years; others as new as 10 years ago. Regardless, the schools of magic are the sole centers of teaching and governing the use of magic on Earth. The preferred method to learn magic is to apply oneself to one of the schools of magic, study and if one is attuned to channel, focus and manipulate magic, one can become a student and/or member of their particular school of magic. It is not uncommon today to even mix up one's training by attending 2 to 4 different schools of magic to create new dynamic ways to access and use one's magical abilities.
As per the United Nation resolution, all magically trained students, proficients, experts and masters must register under the Super-Powered Registration Act (SRA) or be considered criminally negligent (as will the school that didn't register them). Currently all active schools of magic DO NOT agree in registering students and have instead created 'false' records to keep governments out of listing magic users.
Since the Soltan Invasion of Earth in 2000, the general public now readily knows that magic users exist on Earth, and are not (necessarily) considered to be secretive cults anymore. Many magical users (nearly 3/4 of the magic user population) died at the hands of the Soltan invaders. Earth's magic users were also key warriors in the defeat and withdraw of the Soltans. Since the end of the invasion, most people on Earth look at magic users in a positive light, however, there are mystical gangs, rogue magical villains and sects that do evil now and then.
Today, Earth's magical users and students are slowly restrengthening their ranks, drawing in more students every year. A new school of magic, Technomagic, a relatively new school of study and practice, for example, has exploded in new students and followers just over the last three years. Should things continue on the current path, the realm of magic and the people of Earth will find a good balance of helping each other and working together...so long as the Soltans don't return to invade again soon...or there are no other major magical threats looming on the horizon...