I really liked this realm!
I found myself being drawn to using the weapons and gear that were found in this realm, partially because it restricts the Engraved to starting with only starting equipment + Grim Coast equipment, but I'm actually deciding to use one of the new weapons and pieces of gear going forward because I like the unique synergy they provide! I don't feel like they're too strong either; they feel just right.
My biggest criticism is that the final phase of the Rune Lord feels way too easy, especially since I was using the equipment that guaranteed I would always have at least 1 Move available per turn. I think it would be better if the Rune Lord dealt more Harm with their actions. Maybe include "Harm 1" in the first action set so that they're always dealing Harm, no matter what?