ΔE 12.8, fair: the same colour family, but not a straight swap. Steel Legion Drab is more muted, warmer than Black Rose Immortal.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Steel Legion Drab is more muted, warmer than Black Rose Immortal.
The same difference applies the other way round: Black Rose Immortal is more saturated, cooler.
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 Black Rose Immortal on the colour wheel See Steel Legion Drab on the colour wheel
All matches: Black Rose Immortal equivalents · Steel Legion Drab equivalents