I understand that when one "traps the soul" of an enemy, a soulgem in that person's inventory will become filled. This filled soulgem can then be used for enchantment reasons and whatnot.

My question is more towards the actual phrase "soul trapping" - Is soul trapping simply harnessing the mystical, magical energy from a dying creature/person (allowing the soul to reach Oblivion or the Dreamsleeve), or is it literally trapping a soul, preventing that creature/person's soul from going anywhere else? For example, if I were to have a very special soul gem with Almalexia's soul contained inside, do I just have the mystical energy that her departing soul released or do I literally have Almalexia's soul sitting on a desk in Indarys Manor?....

http://www.imperial-library.info/fsg/fc4article01.shtml
Go down to Soul Trapping that should give a better explanation.

The latter. You're literally trapping a soul, even though the mechanics of Oblivion treat it as if you're doing the former. Examples are the named Soulgems in Morrowind, the book Feyfolken, Souls escaping in Daggerfall when you break the enchantment, Prince Ator being placed in a soul to be revived later.

And interestingly enough, according to the new novel, pieces of Daedric Princes' souls can be trapped with a sufficiently powerful item, which actually fragments the Prince (presumably until the pieces are reunited).

I would imagine trapping an entire Daedric Prince would be absolutely impossible, as the Prince is his or her realm, but to trap the spirit essence of an avatar or physical manifestation would be a powerful soul indeed.

Considering an avatar of a prince is nothing but an extension of the prince given physical form, yeah I can see a piece being taken. In which case, I have a piece of Hiricine, and I refuse to part with it.

Well, thank you all for the responses. Almalexia is def going under a heavy lock and key, and to top it off, this makes my RP of soul trapping every Dagoth in MW all the more satisfying...

Not only that, but when an item is enchanted with a soul, that soul remains in it, alive and apparently still intelligent if it ever was. according to the book, That also says to me the Archmage's plan was sound when he soultrapped the dying prince, just the execution was debatable flawed. Hell, with the right tricks and a Daedra Prince a'Tor could return to a bodily form.

For those of us who don't want the book, could you maybe explain to me this a'Tor dude?

First off, you're definitely missing out then.

Second, A'Tor was from TESA: Redguard. He was killed by an assassin, and the archmage tried to trap his soul to revive him later, it only sort of worked and he became the endgame weapon. That means in theory a Daedra Prince could bring him back if he felt like it. But why would he? That a;so means A'Tor is still alive and intelligent inside the weapon.

I always thought that there were two kinds of soul traps. This is all personal speculation.

Type A: The spell quickly processes the soul to be ready to be recycled in the soul sleeve. Because the byproduct of that is magic, the spell stores the magic in a stone capable of doing so. bigger stone/soul= more magic. This is what the player has in Morrowind and Oblivion

Type B: Actually taps the soul itself. Often used by necromancers for use forcing souls into subservience. Used in Daggerfall

Enchanting: through A, you give the weapon the trapped magical byproduct of soul trapping. Through B, you are actually putting the 'soul' or mind of a being into the weapon, and forcing it to do a certain function. Prince A'tor is unique in that he wasn't forced: he wanted it.

I included a philosophical discussion about the nature of soultrapping in the third chapter of my current fan fiction. I intend to expand it in the fourth installment.

The one in the soul gem.

But this wouldn't explain why, in MW, a full soulgem is labeled as the name of the victim. Like trapping a Dagoth, for instance. In OB, regardless of who you took, the soul was just filled with that level, no specific name. It seems that Type B soultrapping happens in both DF and MW, and Type B in OB.

There is a lore explanation for this too--since all necromancy is illegal in Oblivion-era Cyrodiil, the Mage's Guild would only permit the sale and use of Type B Soulgems. In Morrowind certain types of necromancy are illegal, yet other forms of necromancy are actively endorsed by the temple. Therefore type A soultrapping would be common in TES3 era morrowind, and type B soultrapping would be illegal in TES4 era Cyrodiil.

Since we're citing fan-fiction, I've been working on again and off again on a piece of fan-fiction that more or less states that the differences in spellcasting between all of the games are all due to regional differences in how Magicka is channelled, with pros and cons for all of them. So, we could also chock it up to subtle foundational differences in how the spell is shaped.

I think the idea has been at last laid to rest, but there's been this idea that's floated around here on again and off again about whether or not it'd be possible to soul-trap a Daedra Prince. The closest evidence in favor of it was a thought that you could soul-trap his avatar, so long as you probably did it away from his realm where he could so easily change the rules on you and so long as you had something that could hold his soul. The power-sink would then manifest a new avatar, but you would contain a tiny amount of a Daedric Prince. It sort of seems that this is kind of the case, although my bets are that the man-known-as-Umbra was the Vile avatar that had been corrupted by the sword-known-as-Umbra into Umbra and then the power-sink has manifested a new avatar since then.