Skill percents matter a lot here. Is mace even perfected on this duergar? What's his sword skill? How are his defenses? If he is 28 why the hell isn't he boneshattering?

Also, it really does not look like he had the +stats to cover that kotegaeshi. The fight goes downhill quickly after the kote.

What you have here is a warrior with a mace assuming he automatically dicks on assassins and starts spamming lag instead of doing what he needs to do to win the fight. Furthermore, counting who hits more is a shitty metric because you're not factoring in total hp. Duergar warrior is SUPPOSED to tank worse than dark-elf assassin. You only need to hit dark-elf assassin about three times to kill him.

I get so sick of people who bitch about high dex races being overpowered when all they try to do is lag them and think they should win the fight. That's not how it works, nor should it. This fight looks fairly winnable for the duergar, if instead of bashing (one of which he missed and ate a retaliatory throw) he was backhanding, you have at least 3-4 more backhands, maybe even 5-6 dependent on if the assassin used the same exact skills. All of a sudden this fight starts to look a lot different.