Long ago, the guardians were wiped out. The guardians were solely created by the gods to defeat the shadows that would manifest themselves from evil and would blindly attack everything in their path.
One creature who called himself Death, he was given the power of the gods to join these guardians, but it was too much for him.
Driven mad, he learned to control these shadows and used them for destruction.
Two guardians were discovered to have survived, and they were trained to defeat him.
They have been long gone now, and the evil with them.
Most of it, anyway. The shadows still resume to manifest and attack others, and no one knows the cause.
Few guardians are left, the descendants of those two twins, so we are left to fend for ourselves.