Thunder Storm vs Doom Death Black

How close are they?

ΔE 19.3, loose: different enough that you should pick on purpose. Doom Death Black is noticeably lighter, much more muted than Thunder Storm.

Can I use Doom Death Black instead of Thunder Storm?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Doom Death Black is noticeably lighter, much more muted than Thunder Storm.

Can I use Thunder Storm instead of Doom Death Black?

The same difference applies the other way round: Thunder Storm is noticeably 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.