The use of the term “court-martial” in the English-in-brackets translation is for reader convenience (quicker to understand and needs less explanation). The actual Tensei phrase used would translate more closely as “Remove from the Clan” or  a more colloquial “Un-Clan”. But tossing footnotes or exposition-speak into the comic to explain that would be clunky. Clunky over-explanatory drivel is what this text box is for.

Actually its what THIS text box is for, but who's really keeping track?