Tokyo Ghoul: Silver Eyed Witches and Giants of Old, and Crimson stalkers

There was at time where ferocious monsters and creatures pervaded the Earth. There were a diaspora of the most ancient of beings, Titan's who had ravaged and destroyed thousands of lives. Mindless and of sizes greater to any known to man.
They were even hidden in civilizations, of several breeds, eating with an insatiable hunger to feed the empty shells of what they used to be. Others born with language, or a proper though to formulate. However, they were driven away into the lost depths of the planes of humanity near extinction. In other cases, the procreation of humans in small traces multiplied and even thrived beyond the years of civilization in which Yoma had terrorized the entire nation.
Some say to be a mutated genetic of Titans though not the case. Demons, who have taken it upon themselves to impersonate and delve into the world creating a huge threat once again. Thus came the Claymore, who were were chosen to infuse their blood with Yoma in order to get rid of the demons and secure the world. Though through trials of mutilation pain and unending fight to maintain one's insanity, through fear of awakening. The organization held up for centuries past that time, and work along the surface still but not often heard of and more secretive as humanity had begun to fear their history.
And lastly there were ghouls. Ghouls with the power to betray there own and even pass down the lineage of man eaters. Some good, most bad, who are forced to hide in the deep recesses of the nation from the beginning of time. It was their ability to blend in perfectly, that kept them a secret until the time of the new age. Ghouls roam the world with a name that will scar and traumatize the present, until the government steps in dealing with forces far beyond the grasp of any mortal man. Science, the most ultimate sin there is....

WARNING: I OWN NOTHING, and this story will have cross cross overs and is inspired by various works: Tokyo Ghoul, Claymore, and Attack on Titan