The Realms and How They Affect Their Denizens
The mortal realms are often strange and varied, and something that gets highlighted from time to time is that living in a given realm really imbues you with its essence. Some common examples given are those from Aqshy being more passionate and quick to act, sometimes even with quite literal burning body parts; while Shyishians on the other hand are often characterized as pallid and muted in emotion with grim outlooks.
You also see it a lot with Stormcast, different stormhosts or individuals having the energies of their realms a deeply intimate part of their forging. Ultimately, those who are reforged many times also take on the traits of Azyr: booming, thunder voices; eyes like the night sky; air literally electrifying when they anger.
It is, in my opinion, one of the most captivating concepts of the setting.
I also really like to think about what less obvious traits a realm might provide, physical or otherwise.
As someone with bipolar disorder, I have a character that I've been concepting who lived in a twin city: one half in Aqshy, and one half in Chamon. Intense emotions and state of mind, ever-changing. It just makes so much sense to me, and is kinda exciting to explore, that the realms could have profound affects on mental health (and how that might make it more common!) -- what if a populace like this really values Amethyst magic/gravesand for properties of, essentially, anti-anxiety/anti-depressants/mood stabilization?
I'd really love to hear both what examples already exist, as well as what you've come up with for how the realms affect a character -- temporary or permanent!