ΔE 12.5, fair: the same colour family, but not a straight swap. Kronos Flesh is cooler than Guilliman Flesh. They are different kinds of paint: Citadel Guilliman Flesh is a one-coat contrast-style paint and Two Thin Coats Kronos Flesh is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Kronos Flesh is cooler than Guilliman Flesh. They are different kinds of paint.
The same difference applies the other way round: Guilliman Flesh is warmer.
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 Guilliman Flesh on the colour wheel See Kronos Flesh on the colour wheel
All matches: Guilliman Flesh equivalents · Kronos Flesh equivalents