Why is it universally believed that Necropolis is the coolest faction?!

Apparently, because it's a fact. Well, not exactly "cool," but rather "overpowered." Although, there are people with a gothic mindset for whom they are particularly appealing. For example, I personally prefer the Undead (yes, I've made up my mind), because as an anime fan, I appreciate the Japanese influence in this race. Also, out of all types of magic, I've always preferred water and ice. And these guys are simply saturated with water. But that doesn't mean I only play as them. If I did, I would have gotten bored with Heroes a long time ago. I play as everyone to diversify my gameplay.