ΔE 14.1, fair: the same colour family, but not a straight swap. Blackened Steel is noticeably lighter than Death Metal.
Can I use Blackened Steel instead of Death Metal?
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Blackened Steel is noticeably lighter than Death Metal.
Can I use Death Metal instead of Blackened Steel?
The same difference applies the other way round: Death Metal is noticeably darker.
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.