Hades sighed again just thinking about what will happen if he lets the dead roams the world of the living
"Do you know how long it takes me to hunt down the ones that escaped. And there will be souls that escaped. I know it even before I open the gates"
Hades knows that the souls would like the living world very much. And even fi he won the war with the help of his host of the dead, some would possess some mortals or run away to other star system and could create calamity
That is a whole lot of trouble.
Hades would only open the gates of the Underworld if he is truly desperate. Clearly, in his eyes, this does not yet reached the point where he would open the gates of the Underworld and undermine his own foundation
"And how many cause and effect that they created when they were roaming around the Omniverse?"
Poseidon could not say anything to this.