Personally, I completed this mission as follows: Carefully, picking up all the Necropolis creatures, I cleared the path to Isabelle. Then I led her to the Necropolis castle. With Markel, I rescued Frida and headed to Mythgard. By the way, I recommend doing all this quite quickly, as Isabelle starts sending her army to Godric, so we turn all the humans into undead, and they won't leave. On the way, Angels attack. We defeat them (there shouldn't be any major problems). We gather an army in Mythgard and fly to Godric. His army isn't very strong. By the way, the orange hero calms down for a long time if he captures a human city.