Player 1's father is obviously the Warlord.
Player 2's father is also the Warlord. He killed the father in the same way Darth Vader killed Anakin Skywalker.
Player 3's mother sold their soul for the Warlord to fall in love with her.
Player 4's Father is the Warlord and Player 3's Mother. Except after they got together they settled down for a happily ever after.
environmental damage is the answer here.