ΔE 25.2, loose: different enough that you should pick on purpose. Mage Hunter Green is a little darker, much more muted, warmer than Majestic Fortress.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 25). Mage Hunter Green is a little darker, much more muted, warmer than Majestic Fortress.
The same difference applies the other way round: Majestic Fortress is a little lighter, much 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 Majestic Fortress on the colour wheel See Mage Hunter Green on the colour wheel
All matches: Majestic Fortress equivalents · Mage Hunter Green equivalents