Oltrum Bastion

Oltrum Bastion
Oltrum Bastion is the fifth area that you will unlock. It is filled with high-level monsters that are generally harder to kill. This is an area with many zones in it. The different zones are as follows:
 * Oltrum Bastion: Orsheon
 * Oltrum Bastion: Cordia
 * Oltrum Bastion: Maravia
 * Oltrum Bastion: Medius
 * Oltrum Bastion: Flail
 * Illial Temple: Barracks
 * Illial Temple: Lift
 * Illial Temple: Sage Hall
 * Illial Temple: Pure Path

Upon reaching the Illial Temple: Pure Path you will be able to fight the Boss of the Area. Defeating him will unlock the last area called Aincrad.