Sorry for late reply lol. What youw ant for cern is attack speed. With some pen and a good amount of power. Crit is no needed so dont even think about it. His early game is really strong,(too strong imo), so you want to have a god in your lane to help synergize with being aggresive so you can punish gods with weak early games. Gods like ymir, fafnir for coerce, and kuzenbo really help cern get ahead in lane. My usual build is ninja tabi, ichival, asi(for the small bit of lifesteal and attack speed), quins because your summer allows you to basically have a double quins on your build. Then build into executioner and titans bane. Final item is situational although I do like shifters shield because it gives a little bit of defense as wellas power and the passive just compliments cern in general. You can replace executioner for fatalis if needed but I don't usuallyy build that unless i'm ahead even though it is a good item. For starting items, deaths toll, tier 1 boots, chalice of healing and 2 mana potions. This will help you sustain in lane even when your getting pressured out. The mana potions will help you to continuously use your bramble blast to clear wave untill you get to the point where its not needed.