Is it possible for "5x dmg passive skill" to crit? Sometimes with my evicerator I see 20x 30x dmg of normal dmg without any "critical" notification. Whats up with that?
Yes. The passive is "sometimes you'll hit for 5 times the normal damage". Which means that a normal auto attack will be 5* times your normal auto attack damage, but (with let's say a *3 crit mult) a critical strike, instead of doing 3 times the normal damage will do 15 times this damage. Of course, in the example taken, the crit mult is really low, it's often like *10+.
