This mod is a branch of Moonstone and adds nightmare items to the game
This mod can be used without using Moonstone
When you create a new world, you will receive an abyssal gift - the Nightmare Base. If you choose to wear and bear the curse of the abyss, you will be randomly given 3 out of 7 sins.
Each sin will receive an additional stronger curse, such as' blurred vision 'or' ineffective armor '.

However, correspondingly, you will also obtain redemption items for each sin by completing specific tasks, such as the "Disintegrating Magic Mirror" that doubles the number of accessory slots or the "Grabbing Pendant" that turns people into enemies

Of course, this is only a small part
If you don't know how to play the game, you can try using JEI mods to view or access them: NightmareBase