Critical Strike

Critical Strike increases the Random Damage Modifier of an attack by 0.25

• MAGIC or PSYCHIC: From 0.5 TO 1.5
• ANY OTHER ATTACK TYPE: From a Range of [0.25 to 0.75] TO [0.50 to 1.00]

As of 12/08/15 it appears that Phase Step is the only effect which adds Critical Strike to a stack.