Answer:
Someone walked into a room and you heard a crash! Someone died. What happened?
I drift forever with the current down these long canals they’ve made, Tame, yet wild, I run elusive Multitasking to your aid. Before I came, the world was darker, colder, sometimes, rougher, true. But though I might make living easy, I’m good at killing people too.
I cut through evil like a double edged sword, and chaos flees at my approach. Balance I single-handedly upraise, through battles fought with heart and mind, instead of with my gaze.
I'm tall in the morning and short in the noon. I disappear at night but I will be back soon.
Of these things - I have two. One for me - and one for you. And when you ask about the price, I simply smile and nod twice.
What is yours but only used by others?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?