This hole magnet thing... Dovahkiin is gonna be an aspect of Akatosh when he's done right? Kinda like how Martin aborbed all those Dragon souls and became an avatar?
He already is an aspect of Akatosh but yes, he will become a "larger" aspect of Akatosh with each dragon soul he absorbs. It's entirely possible he could accumulate god-like power by the time he's done.
That's about two-thirds accurate. The word "mantling" is getting tossed around so much that its meaning is seriously diluted.
Justifiably, I think. I think once we understand that things like the CoC mantling Sheogorath, Talos mantling Shor, and the Tribunal mantling various daedra are just the most extreme consequences of one of the fundamental laws governing TES metaphysics, I think we'll have a better handle on how it all interconnects. You have a point though, best to figure out a way to separate higher-order uses of this principle from the more common.
Being a servant or a slave is not mantling anything.
It does seem to cheapen the word, but I maintain the difference is a matter of scale and little more. If mantling is the process by which one makes themselves like another thing, either in action, body, spirit, whatever, then mantling is a process with degrees. If the law "like energy seeks like energy" governs mantling, as it seems to, it follows logically that daedric "ownership" or mortal souls is achieved in the same way, whether we call this "mantling" or not.
To preserve the definition of mantling as governing higher-level examples of this phenomenon, I submit the following:
Mantling- A process in which an entity alters the nature of his soul to match that of another, and increases his spiritual mass, in order to attract and absorb the energies of another entity.
This way it's clear that the initial increase in mass is a requirement for mantling, as well as the change in natures. In this way, we disqualify werewolves and others who are absorbed by Daedra, because their spiritual mass does not increase. We disqualify the Dovahkiin's absorption of dragonsouls because while he does increase his spiritual mass, but he doesn't change the nature of his soul, which is already draconic.
But you're right that it does seem, in the observed instances, to require a source of power.
True, which is why I propose that both criteria be met to be considered "mantling".
I'm also not at all sure that it's correct to call the Heart selfless, either in the usual sense of the word or in the literal sense in which you're using it. It's still Lorkhan's heart, not somebody else's heart, and has specific tendencies which are a result of it being Lorkhan's heart, and not somebody else's heart. It's not a battery that could be used to power just any endeavor. The Tribunal did something very specific.
I use selfless to mean "non-sentient". The heart has no will, no ability to act on its own. It's not "untyped" energy or anything, it's still the energy of Lorkhan. The tribunal did not merge with the heart itself, they simply used it's mass to add "gravity" to their own souls, which they then used to mantle other entities, three of the Daedric princes. Dagoth-Ur, on the other hand, not only used the heart's mass as his own, but mantled Lorkhan directly, which is why his power over the heart grew stronger than the Tribunals'.