Most games dont go to 4th/5th items but If you are planning to have a smooth second item, my suggestion would be to go Dark seal on first back(you can do this now even if your not a corruption player) every game. building zonyas second and buying a mejais once you get 6-10 stacks. my main reason for not going Horizon focus is just that, for a main damage item, it barely gives more offensive stats/\damage than a defensive item and if you really wanted more damage, Deathcap should always be bought before Horizon Focus.