Szeth

My current guess is this: He was the fourth son of a noble family and learned to fight, his older brother died and he became the "cook" of the family by moving up in importance. When his brother is killed and the group he's with are either killed or enslaved by Sadeas he then becomes the eldest brother and essentially prince of his group. Then his association with the Knights and then his acquisition of a shardblade elevate him further to potential king of the Horneaters.

Amaram had Oathbringer and Helaran's blade, Rock returned Oathbringer to Dalinar at the end of the book despite the latter's protests that it was no longer his, and I'm not sure if they said what happened to the plate.

Couple things 1) metal minds do have a limit iirc, very small minds can't hold as much juice (information, strength, weight, etc) though the practical limits of filling most decently sized metalminds make this relatively insignificant. (You're not going to spend years sick to store years of health). Compounders like Miles are really the only people who could theoretically push this limit. 2) Nicrosil seems to act as a conduit or buffer that allows access to non-innate abilities. However i think Brandon is nudging us away from the concept of investiture as a binary invested/not-invested and more towards a sliding continuum of barely invested (sentience) and really freakishly invested (shard holders). Sanderson has also made it clear that investiture *can* change a persons soul/body permanently. I'd be curious if a Nicrosil savant might be able to use abilities and metal minds without the nicrosil 'interface'

I would assume that they were "blank" nicrosil metalminds, much like Wayne's "blank" goldmind. The Blank Nicrosil acts as a buffer of sorts, allowing you to use a blank metal that you can't already. For instance if Wayne's goldmind had a blank nicrosil inlay as well then anyone could've used it. As it was only bloodmakers could use it without the buffer. Allrik mentions that 3 is the the most common 'max' number of powers a medallion can bestow, though there are very rare and expensive medallions that have 4 powers. He has to continually swap out his medallion when talking to Marasi because one is nicrosil/iron/duralumin(connection), and the other is nicrosil/iron/brass(warmth) edit: i should clarify a bit further - nicrosil is not a "power" like the other allomantic and feruchemical abilities. It is simply "investiture" and even though not everyone *is* invested, all life in the cosmere has the *potential* to be invested. As a result anyone can make use of a blank nicrosil metalmind in order to access other abilities in blank metalminds/hemalurgic spikes