This Stuff is look like Blue EZREAL. You gonna UP the damage of your skill ( Q and R ) with the muramana & black cleaver and your passive with the runnan ( you will make your double shot on 3 target at each skill )

Why make other thing of 21/9 ?

The lonely change is the 2 point on your CDr for your skill

Berzeker boots : The better boots on adc , more on Lucian cause your R scale with your Attack-speed.

Muramana : REALLLYY TOOOO STRONG ULTIMATE !!!! put on your muramana and make your R on what you want target, it will be sure you will shutdown your enemy.

Bilgewater ( => BRK ) : like all the adc you need lifesteal and with that you up your AS = MORA DAMAGE ON MY ULTIMATE !!!!

Hurricane : like the BRK you up your AS to get more damage on your ultimate but more that, that item make his effect on your passive, you will make your double shot on 3 target

Black cleaver : like on the MF ulti , the R of lucian take the effect of the BCleaver

Guardian Angel : you are an adc you need to make damage on all the teamfight , you have not to died !!