ΔE 15.5, loose: different enough that you should pick on purpose. Titanium White is a little lighter, much more muted than Doomfire Drab.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Titanium White is a little lighter, much more muted than Doomfire Drab.
The same difference applies the other way round: Doomfire Drab is a little darker, much more saturated.
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 Doomfire Drab on the colour wheel See Titanium White on the colour wheel
All matches: Doomfire Drab equivalents · Titanium White equivalents