ΔE 18.2, loose: different enough that you should pick on purpose. Fae Wylds is a little lighter, much more saturated than Necron Compound.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Fae Wylds is a little lighter, much more saturated than Necron Compound.
The same difference applies the other way round: Necron Compound is a little darker, much more muted.
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 Necron Compound on the colour wheel See Fae Wylds on the colour wheel
All matches: Necron Compound equivalents · Fae Wylds equivalents