Just now, Bayushi Shunsuke said:

Insult to Injury states "... dishonor the losing character."

If Mirumoto Hitomi wins a duel against two participants, the two are both considered to be losers.

( As per D6: If multiple characters are involved in the duel on the same side, add their dueling statistics together. They are considered to be one character for the purposes of determining duel results and win or lose together. )

Would Insult to Injury dishonor both, or should it now effectively be read as "... dishonor a losing character."?

It will affect one of the two losers, but not both. You can choose which.

[Tyler Parrott, Jan 17 2019]

My opponent has two characters, one dishonoured, one ordinary. My Hitomi duels both characters and wins and I play Insult to Injury as a reaction. Is the dishonoured character a legal choice for Insult to Injury at this point? It seems like it shouldn't be but I can't see how the various game state change rules apply to this.

Just now, Bayushi Shunsuke said:

My opponent has two characters, one dishonoured, one ordinary. My Hitomi duels both characters and wins and I play Insult to Injury as a reaction. Is the dishonoured character a legal choice for Insult to Injury at this point? It seems like it shouldn't be but I can't see how the various game state change rules apply to this.

The dishonored character is not a legal choice for Insult to Injury (as it could not be dishonored).

[Tyler Parrott, Jan 22 2019]