ΔE 17.6, loose: different enough that you should pick on purpose. Basilisk Green is a little darker, cooler than Occultist Cloak.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Basilisk Green is a little darker, cooler than Occultist Cloak.
The same difference applies the other way round: Occultist Cloak is a little lighter, 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 Occultist Cloak on the colour wheel See Basilisk Green on the colour wheel
All matches: Occultist Cloak equivalents · Basilisk Green equivalents