ΔE 12.1, fair: the same colour family, but not a straight swap. Dark Green Brown is noticeably darker, cooler than Stormvermin Fur.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Dark Green Brown is noticeably darker, cooler than Stormvermin Fur.
The same difference applies the other way round: Stormvermin Fur 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 Stormvermin Fur on the colour wheel See Dark Green Brown on the colour wheel
All matches: Stormvermin Fur equivalents · Dark Green Brown equivalents