The Noble Phantasm document lists Heracles' God hand as an example. Since I assume that's a reference to the show, what did it actually do?
Basically, it resurrected him nine times.
Questions for when Elf comes back
Does a Servant expend an amount of MP per turn they have a Noble Phantasm equipped?
Are the "Passive" Weapon effects always on for the weapon? Do they drain that amount of MP per turn they have it equipped, or just to summon it in the first place?
Are "Barrier" Phantasms and their effects always on?
It depends on the Phantasm. Only Summon, Craft and Reality Marble Phantasms cost anything to maintain- everything else only needs to be summoned.
Passive effects are always on. They do not drain MP for existing, only for being activated.
Barriers must be activated.