ΔE 14.8, fair: the same colour family, but not a straight swap. Runic Gold is noticeably darker, more saturated, cooler than Skullcrusher Brass.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Runic Gold is noticeably darker, more saturated, cooler than Skullcrusher Brass.
The same difference applies the other way round: Skullcrusher Brass is noticeably lighter, more muted, 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 Skullcrusher Brass on the colour wheel See Runic Gold on the colour wheel
All matches: Skullcrusher Brass equivalents · Runic Gold equivalents