I have boat from gore quest and A rank hanger license, but I'm stuck trying to go to Bone Field. After climbing World End Tower, it seems the path is go through some kind of valley -> leave into an overworld map with only a single red dragon enemy -> enter mountain (I think Gasbar mountain? I don't know how to identify the location name) -> enter an ice cave -> then at the end, there is an icicle that I cannot destroy with fire magic. How to proceed? or is there another way into Bone Field that I don't know?