ΔE 9.4, close: similar, with a visible difference side by side. Sand Grey is a little darker, more muted, warmer than Tyrant Skull.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Sand Grey is a little darker, more muted, warmer than Tyrant Skull.
The same difference applies the other way round: Tyrant Skull is a little lighter, 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 Tyrant Skull on the colour wheel See Sand Grey on the colour wheel
All matches: Tyrant Skull equivalents · Sand Grey equivalents