A hero in the 1 position means that they have the highest priority for levels and gold on your team. This is your ‘hard carry’. Heroes that fall into this category are the most item and level dependent on your team. They deal a ton of damage later in the game, and generally build towards damage and survivability.
The 2 position means that they have the second most need for gold and levels. The reasons can vary, but in general they should be farming any lane that isn’t occupied by your 1. The 2 generally builds toward initiation and survivability items, though some heroes benefit from damage items as well.
3 Off lane
The third most farm dependent on your team, generally builds toward team fight/support items such as Pipe/Drum or initiation items. 3 is generally item independent for most damage.
As secondary support on the team, the 4 will build towards the cheaper team fight items like Drum/Mek. The 4 helps on pure support items such as wards, smoke, dust when the 5 cannot afford it.
The 5 mainly uses money on pure support items such as wards, smoke, dust, and sometimes regen and teleports for the 1-2 heroes. It is not uncommon to see a 5 hero purchase nothing more than a boots and a wand for themselves the entire game.
1Phantom Assassin (Safe)
5Vengeful Spirit (Safe)
1Faceless Void (Safe)
2Death Prophet (Middle)
5Crystal Maiden (Safe)