Talk:Alp/@comment-213.119.32.191-20141119154601/@comment-25035274-20141119170635

Mana is Mana is Spirit Energy is Spirit Energy. It's the man's Life Force, or Essence, if you prefer. The only difference between what you're calling (old) and (new) mana is that spirit energy is more concentrated in semen, because semen is the "seed" of new life.

Semen being tightly connected to a man's life force is not a new idea. In many cultures, it's long been believed that when a man impregnates a woman, he's giving a part of his essence away to do so.

The things a mamono does are not just in pursuit of sex, though it is a very high priority for them. Bluntly put, the series creator has outright stated that they have free will, and that they spend time with their husband because they 'enjoy' it, not because they have to. What the series creator says, goes.