User blog comment:Moticolev/manticore anatomy/@comment-24169511-20150102060402

I don't know for sure but I'd imagine spirit energy and really any other magical source of power flows freely trough things without the need for a dedicated circulatory system. Following traditional fantasy ideas, 'mana' simply exists in everyone and everything and doesn't require a biological system to function. From what I know about MGE and the world, I'd say Spirit Energy probably works this way too.