I'm now stuck

[greengimp]

Hello, I'm lvl 44 and have fully cleared everything through the demon area. I'm now sitting with the evil eric standing in front of the caslte with 4 troops all invincible behind him. I have killed everything i can in arlania but i can't kill the mage rezo to progress the story any farther. I have a few quests that tell me to go to riftland but i have no idea how to get there, any help with what i need to do next would be great.