It's already part of the lore to convert grand gems to black gems, and there's many alternative mods, but I found them to be full of incompatibilities or not as accessible as desired. It makes it too much of a big deal to use your grand / black soul gems, which reduces fun.
There's an imbalance: there's too many grand soul gems, but too few grand souls black souls are much more common, but black soul gems are too rare. Reason for this mod is that I felt there was lack of this functionality in Skyrim. Otherwise, it'll convert the Grand Soul Gem into Black Soul Gem. If the Shade of the Revenant hasn't occurred yet, it will tell you when the next one happens. You can do so by first placing a Grand Soul Gem on an Enchantment Table, and then hitting the Enchantment Table with a weapon that has Soul Trap spell. This Skyrim SE mod adds an ability to convert Grand Soul Gems into Black Soul Gems during the 'Shade of the Revenant' (from Oblivion), which happens once every 8 days.
The rest of the content is a copy-paste from LE version. This is Skyrim Special Edition version of this LE mod.
