Azir: Time and perspective
With Taliyah's lore stuff and her teaser, I've seen a lot of people suddenly claiming Azir was evil all along. My 2 cents on the matter disagrees. It's all about the perspective. Azir was a good ruler, but still technically a dictator. Cause that's just how empires work. He also died right after he declared the slaves free, cause of Xerath. Now, Shurima collapses, and her people splinter to the corners of the world. Including the slaves. Naturally, they probably weren't happy and never knew he abolished it right before he got vaporized. He goes down in history as just another slave holding emperor, with the added strike of being the LAST emperor. Ages go by, and suddenly he pops back up in the desert, as a bird looking demi-god looking to restart his empire. People naturally know the tale of him that was passed down and told. Including Taliyah.
TL;DR: Azir isn't evil. His legend has just been warped over the ages by time and misinformation.
Least that's how I see it.
. (And to speak to Xerath as a character, he probably felt like complete GARBAGE once he was given his freedom with the knowledge that he had just betrayed the man who freed him, but at that point he was too far gone for it to matter anyway).