Nightroot Shade vs Druchii Violet

How close are they?

ΔE 20.4, loose: different enough that you should pick on purpose. Druchii Violet is much more saturated, warmer than Nightroot Shade.

Can I use Druchii Violet instead of Nightroot Shade?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Druchii Violet is much more saturated, warmer than Nightroot Shade.

Can I use Nightroot Shade instead of Druchii Violet?

The same difference applies the other way round: Nightroot Shade is much more muted, 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.