Battle of Marathon vs Charred Brown

How close are they?

ΔE 16.0, loose: different enough that you should pick on purpose. Charred Brown is noticeably darker, more saturated, cooler than Battle of Marathon.

Can I use Charred Brown instead of Battle of Marathon?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Charred Brown is noticeably darker, more saturated, cooler than Battle of Marathon.

Can I use Battle of Marathon instead of Charred Brown?

The same difference applies the other way round: Battle of Marathon is noticeably lighter, 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.