This build may seem silly or troll-like, but I assure you it has maximum damage output. Plus it's fun. Everyone seems to think of Lux's laser when they see her on the loading screen. This build however, does not focus on the laser. This build is alllll about that passive. Building ability power is important, but attack power is helpful as well. This build leaves Lux extremely squishy, so having shurelya's and black cleaver help with that. AA Staff and Rabadon give lux her ability power. This is not going to give 1000 ability by any means, but it is sufficient enough for the build. Giving her the Lich's Bane intensifies her passive. Then there is the silly part, giving Lux a bloodthirstier. If you don't die, this will raise her AD exponentially, again, exposing the power of her passive. Best of Luck!