ΔE 19.4, loose: different enough that you should pick on purpose. Tyrant Skull is a little lighter, more muted, warmer than Light Gray Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Tyrant Skull is a little lighter, more muted, warmer than Light Gray Green.
The same difference applies the other way round: Light Gray Green is a little darker, 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 Light Gray Green on the colour wheel See Tyrant Skull on the colour wheel
All matches: Light Gray Green equivalents · Tyrant Skull equivalents