Fall of the Grey Empire

The details of this historical event are a mystery.

All that is known is that a mortal that would later be known as the Hero somehow defeated Arúmil, last of the immortal Grey Emperors, in combat, seemingly killing him (in reality only robbing him of his physical body).

This led to a massive rebellion of the previously subjugated races, who founded their own society, in which no elf was welcome. Greys were slaughtered, halfbreeds were banished and shunned.