ΔE 10.3, fair: the same colour family, but not a straight swap. Necromancer Cloak is more muted, cooler than Tornado Grey.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Necromancer Cloak is more muted, cooler than Tornado Grey.
The same difference applies the other way round: Tornado Grey is more saturated, 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 Tornado Grey on the colour wheel See Necromancer Cloak on the colour wheel
All matches: Tornado Grey equivalents · Necromancer Cloak equivalents