ΔE 22.9, loose: different enough that you should pick on purpose. Bestial Green is noticeably lighter, much more muted, warmer than Caliban Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 23). Bestial Green is noticeably lighter, much more muted, warmer than Caliban Green.
The same difference applies the other way round: Caliban Green is noticeably darker, 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 Caliban Green on the colour wheel See Bestial Green on the colour wheel
All matches: Caliban Green equivalents · Bestial Green equivalents