ΔE 18.8, loose: different enough that you should pick on purpose. Clear Blue is cooler than Leviathan Purple. They are different kinds of paint: Citadel Leviathan Purple is a one-coat contrast-style paint and Reaper Clear Blue is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Clear Blue is cooler than Leviathan Purple. They are different kinds of paint.
The same difference applies the other way round: Leviathan Purple is 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 Leviathan Purple on the colour wheel See Clear Blue on the colour wheel
All matches: Leviathan Purple equivalents · Clear Blue equivalents