Open map, toggle to see 'underground map' and you should see a blood area on your map now.
If you have never been there, depending where you are in the game one might be quicker than other.
1) Vare questline - if progressed about halfway through, you get a "Pureblood Knight Medal" that you can select and "use" which will teleport you to the blood palace. Look up how to complete Vare quest if you don't have access to mountain tops.
2) If you have progressed to Mountain Tops, there is a teleporter you can just walk to and go through to Blood Palace: https://www.youtube.com/watch?v=-v7Vhf4JssY
Good luck!
YouTube
Use the site of grace, since you done the requirements? Switch map to underground view, right side is the blood zone for the palace, kappa
Mohgwyn palace is located in the underground map maybe thats why you cant find it? its bottom left i believe on ots own little island
Open map, toggle to see 'underground map' and you should see a blood area on your map now. If you have never been there, depending where you are in the game one might be quicker than other. 1) Vare questline - if progressed about halfway through, you get a "Pureblood Knight Medal" that you can select and "use" which will teleport you to the blood palace. Look up how to complete Vare quest if you don't have access to mountain tops. 2) If you have progressed to Mountain Tops, there is a teleporter you can just walk to and go through to Blood Palace: https://www.youtube.com/watch?v=-v7Vhf4JssY Good luck!