Thermophile

He obvioulsy had something. I'm inclined to believe that he did have perfect memory, what with him being able to tell if Vin was lying (probably). If he spread rumors about being able to tell if you're lying, and it was true, he probably has the perfect memory too. Mostly because the Lord Ruler didn't seem to do it. If he could gain significant quantities of information he didn't already posses, he probably would have spread word about it around in some way or another. Then again, maybe that's where his ability to detect lies came from.

Oh. I was under the impression that Sazed made Marsh immortal so that he could have an Inqusitor minion. Although, if the Lord Ruler didn't have to use a significant amount of atium, that would make the size of the cache 4 million beads, and the duration of each bead around 75 seconds, which makes even more sense.

Fixed it so it says flawless now (when writing the comment, I was actually really torn on which one to use). And Kwaan said that he could 'memorize entire pages at once' which, although impressive, is not the same as recognizing a guy you saw once twenty years ago, and later learned from a report that he was a spy. However, he could have used the Well of Ascension to alter his own genetic code for that. I did hear somebody mention that he used the Well to give himself super-powered Allomancy.

That situation was supisious. I see no reason it would be anything other than sharp survival instincts. When she went to the meeting with Hoid, though...

He'd be burning none for what, fify years? That isn't much in comparison to a thousand years. I'm mostly just impressed that I actually got a number that's plausible, rather than 15 minutes per bead, or 10 seconds per bead. Although I will admit that this theory is not well grounded.

If I got to have one investiture, it would probably be Feruchemy. Possibly Elantrianism, but the weird hair and skin color (plus the reigonality of its abilities) might make it more trouble than it's worth.

It is stated that malatium is the alloy of atium. I originally thought that each God-metal had one alloy, making for a total of 32 (2 sets of 16) god metals, but it is directly stated that each God-metal forms it's own set of 16 metals. I personally think that there is the pure metal, and an alloy with each of the other God-metals, but that would make malatium an alloy of lerasium and atium (probably) which Brandon Sanderson has stated hasn't happened yet. Although, my biggest problem with the grand total of 272 melats (16 god sets of 16, and one basic set of 16) is the difficulty in thinking of 272 Allomantic, Feruchemical, and Hemullugrical properties, but that's just me.

Alright, obviously copper compounding can't give you information that you didn't already have, but it could increase their clarity. I refer to this (imperfectly quoted) line from Breeze: "I can't go anywhere where the Lord Ruler will be, because he's seen me before, and you know he has a flawless memory" Therefore, copper compounding allows you to enhance memories to the point where you can remember everything you've ever seen perfectly. In the AoL, a copper compounder could skim every book ever published, and be able to recite any of them word-for-word. Sorry if this was a bit obvious, just wanted to put it out there.

The Lord Ruler is (was) literally a thousand years old. I feel like he'd still need a lot of the stuff considering how fast it burns. Besides, considering that his bracers were confirmed to contain a very small quantity of atium, he'd have to burn it very often.

When I recently reread the Mistborn books, during the part with the atium stash, I wondered how much it would acutally have containted. After all, the Lord Ruler would have to burn it literally all the time in order to compound age storing, and not die of old age. Even if the Lord Ruler kept it on a very low burn most of the time (higher when there is anybody to see him) the speed at which atium burns means that he couldn't possibly need less than 10 beads per day. The prisoners in the pits of hathsin get one bead a week. This means that, simply to keep the Lord Ruler alive, there would have to be more than 70 prisoners on average. When Kelsier takes over the pits, he mentions that there are only a couple dozen guards [citation needed]. This means that there could not have been all that many prisoners. Combined with the fact that being sent there is extremely rare (the old guy in the first book had only seen it happen once), I'm thinking that the pits have an average of 100 prisoners at a time, each getting an average of one atium geode a week. With the Lord Ruler using ~70 of those beads and 10 going to the nobility, that leaves 20 going to the kandra each week. Remember, a lot of the atum the nobility gets goes to the kandra, so let's say that the kandra get 25 a week. With some quick math (and assuming that Scadrial has the same length year as Earth) we can conclude that the kandra's cache should have contained (roughly) 1.3 million atium beads. With that number, we no longer have to worry about it being too small an amount, but it could be too large. In the fight against the colos where the atium got burned up, there were about 200 atium mistings, plus Eland, and that they were fighting for roughly 3-5 hours straight. With each misting having to burn a total of 65000 beads, this means that each geode worth of atium would have to take roughly 3.6-6 minutes to burn. Sounds about right. And with that, we can conclude that if I was correct with my calculations, Brandon Sanderson likely was too.

Is there any way for me to move this topic, or does a mod have to do it?

A feruchemist who used nicrosil to store investiture would need to have multiple investitures (other than feruchemy). With that, you'd be able to weaken those other abilities while storing it, and increase them wihile using it. This could also be part of how the Lord Ruler became such a powerful Alamancer, as nicrosil compounding would make Allomancy much more powerful. That's the best explanation for the feruchemical use of nicrosil I could think of.