ΔE 12.5, fair: the same colour family, but not a straight swap. Succubus Skin is noticeably lighter, cooler than Shadow Flesh.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Succubus Skin is noticeably lighter, cooler than Shadow Flesh.
The same difference applies the other way round: Shadow Flesh is noticeably darker, warmer.
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 Shadow Flesh on the colour wheel See Succubus Skin on the colour wheel
All matches: Shadow Flesh equivalents · Succubus Skin equivalents