Attempted metaphorical paraphrase: so Generic Immortality changes the state of your essence from liquid to solid. This prevents you from changing yourself. Your character will not deepen, your virtues and vices will remain at a constant level, and your perspective becomes fixed. It doesn't mean you cannot choose to do X action over Y action, but that your basis for the final decision is always filtered through the same thought processes and emotional reactions. In exchange for these limitations, you become unable to die and gain a magical/cosmic power boost.
Mantled Immortality retains the stipulations above, but adds to them. For instance, Molly, in becoming the Winter Lady, is not only having her personality frozen (haha), it is being added to whilst being frozen. The tendencies of Winter (predation, coldness, pragmatism, ruthlessness) are slowly being added to who she is with every choice she makes to embrace those aspects. Once added, they are immutable. She will eventually become a completely solid entity of Winter, no longer capable changing and choosing as a Mortal would. In addition to these personality changes, because it's the Winter Mantle, the inability to deliberately lie has been ingrained into her, as has an essential vulnerability to cold iron. On the positive front, she gains a greater power boost than Generic Immortals would because of the additional restrictions of Winter and Fae.
Am I understanding correctly?
You got it right save for the difference between "Mantled Immortality" and "Generic Immortality". Everything I describe would, as far as I understand things, would fall under the "Mantled Immortality" category. What Id call "Generic Immortality" would be more like "Racial Immortality" a combination of Agelessess and Supernatural Durability, but they can be killed any day of the week (if you are strong enough, anyway). Lara or Arianna or even Lea are all examples of beings that will not naturally Die, but that do not have actual Mantles and so can be killed outside of Conjunctions. Of those example, only Lara has a Soul and is capable of Free Will, making her (and the White Court) an example of the Half-born that are still Human enough for some purposes (like being Winter Knight, for example). By contrast, the Queens and any Eldests we've met (Cat Sith, Scarcrow, Eldest Gruff) are Mantled beings that would fall under the framework outlined above. Also Ill add that per WOJ the Lying bit and the general focus on Duty and Obligation are not universal, those are particular to the Fae courts and fae Mantles. In the case of a Darkhallow birthing a new Mantle, it would most probably fall under the "You Are What You Eat" law of things such that even if you went that route, youd be warped by the nature of the Power you ate (in DBs case it was Hunter spirits and lots of Death, likely to birth a naturally hostile entity) just as much as Molly is being pushed by the Winter nature of her mantle now.
Note that I have no real idea how Angels fit into this, as they are the only known example of a truly immortal entity that also has a Soul (since they are ALL soul).
