ΔE 25.4, loose: different enough that you should pick on purpose. Anthraquinone Blue is a little darker, much more saturated, cooler than Diabolic Plum.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 25). Anthraquinone Blue is a little darker, much more saturated, cooler than Diabolic Plum.
The same difference applies the other way round: Diabolic Plum is a little lighter, much 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 Diabolic Plum on the colour wheel See Anthraquinone Blue on the colour wheel
All matches: Diabolic Plum equivalents · Anthraquinone Blue equivalents