You mean events.txt (the only eligible txt file)? That only mods or adds titles & descriptions, not triggers & actual character traits.
Chances are the extra titles & descriptions will never show up, and if they do, they wont have an actual impact on any stats.

Sure, you can change "No Mercy" to "Goblin eater" and change the description, but it will still give you +2 dread -1 morale even if you type in something different, the game traits is still named:
prisoner_killer2
which is hard coded.

So it cant be done. Sorry.