Here's all that I have to say to that Klingon:
Poor Pava, ones heart could almost bleed.

But then that's what makes him such a compelling character. He is a brutal and bloody killing machine. Ruthless and without compunction when it comes to killing if he feels it necessary. However, his causes and purpose in the past have not all been honourable and this aspect to him and his sheer bloodiness means to say he doesn't become a caricature tough guy with the best skills. Instead he is a deeply complex and dark brooding figure. Who chooses to make himself alone rather than find the life this Klingon warrior has found.
And yes this Klingon warrior is immediately a compelling character we all want to know more about. His shared history and the skills he has learned from Pava mark him as very dangerous and very shrewd. I love how he handles Pava and has enough foresight to clear the planet before he releases the killing machine.
However, as decried as Pava is in this piece, painted the killer and butcherer I think his words do ring true and serve as a lesson to nay new recruit to Starfleet.
"You are whatever the situation requires you to be. On a First Contact mission you are an explorer. On a diplomatic mission you're a peacekeeper. And when a Federation colony is invaded by a horde of slavering war beasts, you're supposed to be a soldier. You took an oath to defend the Federation, and I don't recall there being any provisos about only doing so when it's safe or convenient for you."
Great stuff. Absolutely fascinating.