ΔE 19.1, loose: different enough that you should pick on purpose. Monastic Green is a little darker, warmer than Dark Kraken.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Monastic Green is a little darker, warmer than Dark Kraken.
The same difference applies the other way round: Dark Kraken is a little lighter, 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 Kraken on the colour wheel See Monastic Green on the colour wheel
All matches: Dark Kraken equivalents · Monastic Green equivalents