Unlike the first defination, the Unversed are beings created from Foul emotions. The rest is true.

SPOILERS

Vanitas (Also referred to as 'The Boy in the Mask', or 'The Apprentice') is the cause of the unversed that relentlessly attack Terra, Aqua, and Ventus in the game Kingdom Hearts: Birth by Sleep.

When you eat dirt for the first time and leave your family to build a shack in the woods

Due to a translation error, North Americans have been using the term "Unbirth" as the new mysterious enemy in Kingdom Hearts: Birth By Sleep. But, the real english term is "Unversed"

An Unversed is "the opposite of human life"