ΔE 13.2, fair: the same colour family, but not a straight swap. Magic Blue is a little darker, more saturated, cooler than Nighthaunt Gloom.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Magic Blue is a little darker, more saturated, cooler than Nighthaunt Gloom.
The same difference applies the other way round: Nighthaunt Gloom is a little 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 Nighthaunt Gloom on the colour wheel See Magic Blue on the colour wheel
All matches: Nighthaunt Gloom equivalents · Magic Blue equivalents