ΔE 20.9, loose: different enough that you should pick on purpose. Sekigahara is noticeably lighter, more muted, warmer than Blood Thorn.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). Sekigahara is noticeably lighter, more muted, warmer than Blood Thorn.
The same difference applies the other way round: Blood Thorn is noticeably 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 Blood Thorn on the colour wheel See Sekigahara on the colour wheel
All matches: Blood Thorn equivalents · Sekigahara equivalents