No one can recall when they first walked among us.
It might have been when the mystical Kabal emerged from the Middle Ages to the present time through the use of arcane arts. Her sole purpose; to mentor the noble champion Crusader, along with his companion at arms the technologically advanced armored Templar.
Perhaps it was during the 80's when the alien craft crash landed in the Arizona desert. Stranded upon our world, four elemental guardians, each hailing from the vast unknown depths of the galaxy.
Even earlier others still recall the heroic exploits during the Second World War, of Sergeant Steel and his squadron the Sentinels, battling the nefarious Nazi The Blood Baron.
Others whisper the legend of when 100 Roman soldiers sacrificed their lives to bestow their essence, empowering Earth's mightiest protector Centurion, which continues to be passed down through the generations.
One thing is certain...
Their demographic increases as time continues on. What was once considered a freak of nature, a rare occurrence is no longer.
They walk among us.