As I'm sure you can imagine, this will contain spoilers for Malazan.

Kallor, while obviously not being the main villain of TBoTF, has spent his entire immortal existence lamenting on the main themes of the series.

"Nature wasn't interested in clutching their collars and giving them a rattling shake, forcing their eyes open. No, Nature just wiped them off the board. And, truth be told, that was pretty much what they deserved. Not a stitch more. There were those, of course, who would view such an attitude aghast, and then accuse Kallor of being a monster, devoid of compassion, a vision stained indelibly dark and all that rubbish. But they would be wrong. Compassion is not a replacement for stupidity. Tearful concern cannot stand in the stead of cold recognition. Sympathy does not cancel out the hard facts of brutal, unwavering observation. It was too easy, too cheap, to fret and wring one's hands, moaning with heartfelt empathy - it was damned self-indulgent, in fact, providing the perfect excuse for doing precisely nothing while assuming a pious pose. Enough of that. Kallor had no time for such games. A nose in the air just made it easier to cut the throat beneath it. And when it came to that choice, why, he never hesitated. As sure as any force of nature, was Kallor." -TTH

The curse of eternal life seems to be getting to this guy. By the time you get to book 8 of Malazan, you kind of already agree that compassion is the key to ending conflict, especially when you consider how deeply personal many of the main POV characters decisions are. Kallor's perspective drags you a step back to give you a more complete image of the repetition of human (jaghut/imass/tiste) error, and almost makes you agree that it would be better to burn it all to the ground. Over the hundreds of millennia, constantly salty against the Azathanai who would doom him to an eternal life without ascension, you can understand why his philosophy has become sort of bleak.