ΔE 7.7, close: similar, with a visible difference side by side. Magic Blue is a little lighter, more saturated, cooler than Stormfiend.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Magic Blue is a little lighter, more saturated, cooler than Stormfiend.
The same difference applies the other way round: Stormfiend is a little darker, 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 Stormfiend on the colour wheel See Magic Blue on the colour wheel
All matches: Stormfiend equivalents · Magic Blue equivalents