ΔE 12.7, fair: the same colour family, but not a straight swap. Magnus the Red is a little lighter, more muted, warmer than Warlock Purple.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Magnus the Red is a little lighter, more muted, warmer than Warlock Purple.
The same difference applies the other way round: Warlock Purple is a little darker, more saturated, cooler.
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 Warlock Purple on the colour wheel See Magnus the Red on the colour wheel
All matches: Warlock Purple equivalents · Magnus the Red equivalents