The card may be
in a company, not
on a company.
I propose the following erratum:
Playable at a tapped or untapped Shadow-hold
![Shadow Hold [-me_sh-]](./images/smilies/me_sh.png)
. May not be attacked. Discard this ally if its controlling character is wounded. Tap this ally to remove the effect of an attack against its controlling character's company that states: attacker chooses defending characters. Cannot be duplicated
in a given company.