That's good because I didn't mention Prydaz. Mentioned everything else who can eliminate: DPS check for low ilvl and / or Meta usage defensively (impossible without shoulders). Darkness is not about reaching boss only, it's also about getting into with high life pool. The numbers I entered 2nd or 4th transition with less than 50% was fatal for the only tick I received and shoulders is kind in that regards cause you can use Meta in 2nd transition. The best for no shoulders people is to use it in first arcane phase during is first arcane barrage cast to completely ignore damage and stun it as well.
This + Netherwalk completely saved my bad luck attempts before I was confident getting into P2 everytime.