Multiple champions can harvest the same soul for the full value. Note that the souls are instanced per Harvester, and you will not be able to harvest souls that you were not personally in range to spawn.
Dark Harvest is incredibly strong in ARAM mode, as a lot of teamfights happen regularly leading to a lot of takedowns, which means a lot of stacks.
Works like an on hit proc, thus only being applied by abilities that interact with the former.
Passive: Champions, large minions, and large monsters drop Soul Essence on death, which you can collect by moving nearby. Collecting Soul Essence empowers your next attack versus an enemy champion or structure within the next 20 seconds to deal 40 - 80 (in base al livello)(+ Total Soul Essence)(+ 25% bonus AD)(+ 20% AP)bonus Adaptive damage.
Champion souls grant 6 Soul Essence; large minion souls grant 4 Soul Essence; and large monster souls grant 2 Soul Essence. Select champion summoned units are classified as large minions.
After collecting 150 Soul Essence you become Soul Charged, increasing the time to trigger the empowered attack to 300 seconds.
Adaptive: Deals either physical or magic depending on which would deal the most damage.