After finding Reith and exiting the cave, you will be in Yason-Roven Plains. There is a battle in this area that could be confusing. Use the following steps to complete it. Instead of starting the battle with Calintz slashing away at the Blast Worms and Orha, have Reith run North on the screen towards the cliff. Basically get Reith as far away as possible from Orha. If you desire, you can also defeat the Blast Worms and Orha, but running is best.
Magna Carta: Tears Of Blood