Elven purge

Military: War

At the end of Second Heraklionian Civil War, Yuan-Ti came up with another punishment for those who dared to rebelled against their masters. They found out that elves were crutial for this war to last so long and cause so hard loses. So they've started special processes which were designed to cause extinction of elves.
  For every elvish children was born, its parents had to die. This caused a massive decrease in elvish population and massive attempts for escape to Seldarian Forest as this was the only part of the continent that wasn't fully under the control of Yuan-Ti.