tbh I build lucian rly normally, but that was before his e had mana cost
IE/BORK(so situational tbh) -> boots (also situational btw cd/atk spd) -> PD -> BT -> LW -> GA/BV/BORK
really depends on how far the game progresses and how far ahead you go, but whenever I played lucian before that whole cost thing, it was p normal for me to go IE > BER > PD > BT > LW > BORK
that's always been my build for him though, some people just pop youmuus for that damn ult of his but i never use it in fights for some reason so i just do whatever