Goddess Glow vs Darkoath Flesh

How close are they?

ΔE 16.8, loose: different enough that you should pick on purpose. Darkoath Flesh is a little lighter, warmer than Goddess Glow.

Can I use Darkoath Flesh instead of Goddess Glow?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Darkoath Flesh is a little lighter, warmer than Goddess Glow.

Can I use Goddess Glow instead of Darkoath Flesh?

The same difference applies the other way round: Goddess Glow is a little darker, 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.