ΔE 13.6, fair: the same colour family, but not a straight swap. Warpfiend Grey is much more muted than Lavender.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Warpfiend Grey is much more muted than Lavender.
The same difference applies the other way round: Lavender is 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 Lavender on the colour wheel See Warpfiend Grey on the colour wheel
All matches: Lavender equivalents · Warpfiend Grey equivalents