ΔE 12.2, fair: the same colour family, but not a straight swap. Kingdom Blue is more saturated, cooler than Alien Purple.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Kingdom Blue is more saturated, cooler than Alien Purple.
The same difference applies the other way round: Alien Purple is 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 Alien Purple on the colour wheel See Kingdom Blue on the colour wheel
All matches: Alien Purple equivalents · Kingdom Blue equivalents