I see, they will take it into account.

Yep, the realm of the dead is simply layers of spirits, the deeper they go the harder it is to get out, but they will also find more mystical of creatures like demons or people that have been dead for longer periods of time. So if they go so and so deep, it is unlikely they will pull themselves out before the battle is over, but they may find the ghost of a spartan. 

That is why they usually have minor elemental demons, or animals.