ΔE 12.0, fair: the same colour family, but not a straight swap. Ashen Blue is noticeably darker, cooler than Stormfang.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Ashen Blue is noticeably darker, cooler than Stormfang.
The same difference applies the other way round: Stormfang is noticeably lighter, 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 Stormfang on the colour wheel See Ashen Blue on the colour wheel
All matches: Stormfang equivalents · Ashen Blue equivalents