[quote]Anything that doesn't have human mana vessels connected to a soul will be classified as a "spirit", i.e. non-human, and needs a human partner to achieve full power in the human world. More specifically, this applies to soulless beings and magical artifacts that are technically not spirits, but are still treated as spirits by the Seals for this reason.[/quote]
Added this to the first post, in the section about soul pacts.

[quote]A mind is an exceedingly complex object, only marginally less complex than the soul itself. Thus, trying to replicate a mind is highly difficult, and the result will usually be an imperfect copy. And because of the complexity of the copying process, the exact imperfections are likely different each time, pseudo-random and almost impossible to predict. Copying a copy will cause the imperfections to accumulate, eventually causing the copies to be very different from the original, and from each other too.[/quote]
Added this to section 2.1.1 of the Codex.