Some strange idea struck me while brushing my teeth. Lasso and Frankfried were originally a gun and sword, respectively. Inanimate objects. Yet, after they "devoured" their Devil Fruits, they became living beings. From a biological standpoint, life can only come from existing life, not from the inanimate (at least not yet) so this raises the question - why are Lasso and Frankfried alive? Why aren't they simply a Dachshund-shaped gun and an Elephant-hilted sword?
Something mentioned several times over the course of the series might have an answer - one of the theories of Devil Fruits is that each fruit contains a "devil" that grants someone powers. This devil might be merely mythical or metaphorical, but it's appeared numerous times to explain certain phenomenon; Jabura for example believed that a Devil Fruit user who comes in contact with another fruit will have his inner demon do battle with the demon in the yet-to-be-eaten fruit. Early in the series, the fruit's "demons" are said to be the beings that the ocean rejects, hence the paralysis when in contact with a body of water.
So, consider this. Perhaps Lasso and Frankfried, who were originally merely objects, became "possessed" by the demons of the Devil Fruit. That is to say, rather than the fruit's demon merely existing inside of a DF user and granting the user powers, they've taken total control of the user's body.
In Naruto terms (pardon the crude analogy), each DF user has a Tailed Beast inside him/herself that grants powers. In Lasso and Frankfried's case, in which the objects that became DF users were not alive, the Tailed Beasts manifest physically through the objects themselves, like how the Beast of Darkness takes control of Guts and physically alters Berserk's Armour in the Berserk manga.
What's the implication of this? It gives us some idea of what the DF's actually are - are they a magical item, or the super advanced technology of a long existing civilisation during the blank century? Are these demons immortal, do they become fruits once a DF user dies and merely pass onto the next user? What could be their objective?
Thoughts/ideas/contributions are most welcome.