There are literally 6 endings I have gotten through a combination of different dialogue choices and different fighting styles.
I've found more than what the "All endings" videos on youtube show.
You can actually beat the hero and make him give up, you can refuse to fight the hero completely, you can be unyielding and cruel in your dialogue then soften your tone at the end, you can be soft in your dialogue at first and then decide not to yield in the end.
You can *almost* make the hero give up, and then let him defeat you.
They all give different endings and there are different variations of the "yes" and "no" options at the end depending on how you played.
[EDIT] I had only gotten 5, but I got the 6th now and the dev confirmed that's all there is.