ΔE 8.9, close: similar, with a visible difference side by side. Gray Violet is more muted than Necromancer Cloak.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Gray Violet is more muted than Necromancer Cloak.
The same difference applies the other way round: Necromancer Cloak is more saturated.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Necromancer Cloak on the colour wheel See Gray Violet on the colour wheel
All matches: Necromancer Cloak equivalents · Gray Violet equivalents