I would add "this turn" at the end of the sentence
Concise is not always strict.
"this turn" instead "in his last company" would also match a situation where a character that was eliminated by a body check in M/H phase and a shadow‐magic‐using character were in the same company, but only slightly earlier - in organization phase, not at point "when the former was eliminated".
Now I realize that my last proposal was not strict too.
"Playable on a character that was eliminated by a body check this turn if you have a shadow‐magic‐using character that was in his last company."
also matches situation when a character has been eliminated while being imprisoned and a shadow‐magic‐using character was in his last company (some turns ago).
It also matches following situation:
A character and a shadow‐magic‐using character are in the same company when former is eliminated by body check.
Then the former is returned by Freeze the Flesh and then the former is eliminated by mean other than body check (corruption check, Pallando the Soul-keeper, The Ithil-stone).
(Another copy of) Freeze the Flesh still could be played on such character. After all he " was eliminated by a body check this turn" and "a shadow‐magic‐using character was in his last company" (and even in the same turn).
My current proposal:
"Playable on a character eliminated by a body check that was eliminated this turn if you have a shadow‐magic‐using character that was in his company, when the character has been eliminated."
"Playable on a character eliminated by a body check" would indicate a reason for which he is currently eliminated.
P.S. Uff.. now i have a more leniency for analphabetism of ICE authors.