ΔE 12.4, fair: the same colour family, but not a straight swap. Rust Brown is a little lighter, more muted, warmer than Wyvern Fury.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Rust Brown is a little lighter, more muted, warmer than Wyvern Fury.
The same difference applies the other way round: Wyvern Fury is a little darker, more saturated, cooler.
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 Wyvern Fury on the colour wheel See Rust Brown on the colour wheel
All matches: Wyvern Fury equivalents · Rust Brown equivalents