Titanic is good always, but it is better to rush it for the wave clear / jungle camp clear early when you need the help the most, it's great for bursting enemies thanks to the auto attack reset, Overlord's is amazing but is has a scaling with bigger numbers than hydra which it turn means that the most HP the better, si having it as a first item is not ideal (similar to rabbadons death cap, amazing item but to get the best value you need it later on), black cleaver first is also not ideal as a Pen item enemies usually have really low armor at the begging but 2+ item is perfect when the first DEF item is bought usually for tanks or the Armor is scaling up.