For our purposes, willpower as a statistic on Arx differs from composure in so much that composure is about resisting being compelled to take an action, while willpower is about overcoming a state one is already in. As a rule of thumb, composure is to stop oneself from starting an action, while willpower snaps out of an action they are doing. As a scale:
0:Has no concept of self, feral, will just keep chewing regardless.
1:Yeah, they are definitely sleeping in.
2:The average human can vary between iron willed determination in some cases and in others they buckle like a belt.
3:Never late from hitting the snooze button.
4:The kind of individual that will nonchalantly lock themselves in a room to kick an addiction cold turkey.
5:The poisoner really should have used more to keep them down.
6:Berserkers come to them for guidance on how to snap out of it.