The last effect of this card simply states: "Until this battle ends, negate his straightening", common sense reading of the card tells me that this refers to the duel's loser, however the way its templated and the way many previously printed cards have interacted leads me to think that this references the enemy personality. Meaning that even if you initiate and lose the duel, effects that would later straighten your personality during that battle would not be negated?
Assaults Without Finesse
A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
The last effect of this card simply states: "Until this battle ends, negate his straightening", common sense reading of the card tells me that this refers to the duel's loser(.)
It is.
http://rules.l5r.com/CE_Special_wording_rules#Pronouns: "Pronouns and pronoun-like terms, like 'him'... refer to the last possible thing mentioned in the text that the term would logically refer to."
Duel's loser.