Cern's 2 is basically a kuku nado with a burst if you hit the initial shot, by going int we trade some burst damage for a lot of tick damage and by double stacking we make up for the lost strength. At item 3 we're trying to force every fight we can in mid on cool down and then take advantage of your incredible clear to force OBJ's or hyper farm mid camps.
Better damage less cooldown
Turns you into a mage adc, less ability damage and cooldown but more AA damage, at full build should put you at almost +100% attack speed
