ΔE 18.1, loose: different enough that you should pick on purpose. Naphthol Red Light is noticeably lighter, more saturated than Berserker Bloodshade. They are different kinds of paint: Citadel Berserker Bloodshade is a wash/shade and Golden Naphthol Red Light is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Naphthol Red Light is noticeably lighter, more saturated than Berserker Bloodshade. They are different kinds of paint.
The same difference applies the other way round: Berserker Bloodshade is noticeably darker, more muted.
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 Berserker Bloodshade on the colour wheel See Naphthol Red Light on the colour wheel
All matches: Berserker Bloodshade equivalents · Naphthol Red Light equivalents