ΔE 23.8, loose: different enough that you should pick on purpose. Legacy Blue is a little lighter, much more saturated, warmer than Remove Mana.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 24). Legacy Blue is a little lighter, much more saturated, warmer than Remove Mana.
The same difference applies the other way round: Remove Mana is a little darker, much more muted, 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 Remove Mana on the colour wheel See Legacy Blue on the colour wheel
All matches: Remove Mana equivalents · Legacy Blue equivalents