"War does not determine who is right -- only who is left." -- anonymous
In the beginning, all Realms were once united. Their people once passed through gates connecting each of the Realms together freely. Moot Points they were called, for they were often mundane and otherwise unassuming to the naked eye; one would have to know what they were looking for to gain access to it. In these days, magic flowed just as freely as travelers between Realms, connecting the varying races and people in ways not otherwise possible. Not only could one be born with a natural ability for it, but reservoirs could be found dotted across natural landscapes just waiting to be harnessed. With such easy access, many worried one I'll of heart and intentions could just as easily harness those magical sources to wreak havoc on the Five Realms.
And so, the Wardens were born.
These men and women of various descent had been different than most -- they could easily hold more magical energy than the average person and were better known for their ability to give and take magic as they saw fit, be it natural source or being alike, with many known for being powerful wizards or warlocks. And so these people had been tasked with safeguarding these natural springs of magic, often being appointed Keepers to better aid them. At first, these safeguards aided in keeping the Realms aligned and peaceful.
But war and greed always find a way.