ΔE 31.5, loose: different enough that you should pick on purpose. Emperor's Children is noticeably lighter, much more muted than Magenta.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 31). Emperor's Children is noticeably lighter, much more muted than Magenta.
The same difference applies the other way round: Magenta is noticeably darker, 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 Magenta on the colour wheel See Emperor's Children on the colour wheel
All matches: Magenta equivalents · Emperor's Children equivalents