@RumikoOhara I love Eris! What powers do you think Lily would’ve had if she was the daughter of Eris?
Well she is the part of war that either begins it or is what some call the fog of war, confusion in battle; she is after all Ares sister. It was she who began the Trojan war because she was slighted so she cast the golden apple of Discord among three Goddesses there which said "To the Fairest"
In some myths she's the turning of battle either from victory or defeat the Goddess which fits best "No Plan of Battle survives contact with the enemy"
Pain is also part of her realm so in a couple of myths she's said to carry a scourging whip so a daughter she has might be armed with such a weapon