Demigod Flames vs Marigold Yellow

How close are they?

ΔE 16.8, loose: different enough that you should pick on purpose. Marigold Yellow is noticeably lighter, more saturated, cooler than Demigod Flames.

Can I use Marigold Yellow instead of Demigod Flames?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Marigold Yellow is noticeably lighter, more saturated, cooler than Demigod Flames.

Can I use Demigod Flames instead of Marigold Yellow?

The same difference applies the other way round: Demigod Flames is noticeably darker, more muted, warmer.

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.