So my friends and I are thinking about dipping our toes in AoS and I've been looking over the 3rd edition rules availible online. Somethings just haven't been sitting right with me so I wanted to just check on the thing that's unsettling me the most.

So in the rules I noticed for the battle round there is what's essentially an initiative roll for who fights first. The way units fight is determined by rules such as first strike, last strike, and not having either of those rules.

So I'm just wondering how common first strike is as an ability on a unit or even in an army. Because without really knowing its prevalence it kind of makes the battle roll seem arbitrary and unnecessary to me.