ΔE 18.3, loose: different enough that you should pick on purpose. Mage Hunter Green is a little lighter, warmer than Dark Reaper.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Mage Hunter Green is a little lighter, warmer than Dark Reaper.
The same difference applies the other way round: Dark Reaper is a little darker, 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 Dark Reaper on the colour wheel See Mage Hunter Green on the colour wheel
All matches: Dark Reaper equivalents · Mage Hunter Green equivalents