Once you manage to get Devourer you MUST be able to fully stack it until minute 20 when you will have Guinsoo's Rageblade in order to completly snowball the game,destroying enemy team without them being able to retaliate or gain ground.Also if you actually took a look at the build and the masteries you should have realised by now that it focuses around basic attacks and "On-Hit-Effects" like magic damage on hit,stacks, or "+ damage%".This particular build should be able to carry you at least to Diamond if not Higher if you play with it properly.I am a Xin Zhao main and it actually took me hundreds if you not thousand of hours to perfect the build, test it, and be able to also perfect every jungle path and strategy with Xin Zhao in order to have reached the Top 25 Xin Zhao in all servers.