ΔE 12.0, fair: the same colour family, but not a straight swap. Transparent Yellow Iron Oxide is a little lighter, more muted than Fiendish Yellow.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Transparent Yellow Iron Oxide is a little lighter, more muted than Fiendish Yellow.
The same difference applies the other way round: Fiendish Yellow is a little darker, 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 Transparent Yellow Iron Oxide on the colour wheel
All matches: Fiendish Yellow equivalents · Transparent Yellow Iron Oxide equivalents