ΔE 21.1, loose: different enough that you should pick on purpose. Cerberus Brown is a little lighter, much more muted than Fiendish Yellow.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). Cerberus Brown is a little lighter, much more muted than Fiendish Yellow.
The same difference applies the other way round: Fiendish Yellow 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 Fiendish Yellow on the colour wheel See Cerberus Brown on the colour wheel
All matches: Fiendish Yellow equivalents · Cerberus Brown equivalents