The book contains another two pages of content that describe the situation of this item being passed among transcendent individuals during the Fourth Era.
The Fourth Era was an age of darkness and chaos. Dark creatures dominated the vast majority of the material world, and cannibal clans ran rampant. The intelligent races could only assist each other for mutual survival, leading to relatively good relations among humans, elves, dwarves, elfin kind, and dragons in the early Fifth Era, which directly resulted in the emergence of multi-racial hybrid creatures.
For example, Miss Fiona Drago, whom Shard encountered at the ruins of the Gadis Library in the Valley of Dead Silence, clearly has both human and red dragon bloodlines.