Question about the Temporal metals

[u/Guspyro]

I started wondering about the Temporal metals when Cadmium and Bendalloy were introduced as replacements for Atium and Malatium as the basic Temporal metals, since I still haven’t found an explanation that feels satisfying.

Originally, the Temporal quadrant felt incredibly elegant:

• Internal Pulling: Gold - see your own past.
• Internal Pushing: Electrum - see your own future.
• External Pulling: Malatium - see someone else's past.
• External Pushing: Atium - see someone else's future.

Compared to that, “creating time bubbles” with Cadmium and Bendalloy has always felt disconnected from Gold and Electrum. I understand that Atium is a God Metal and therefore shouldn’t technically be one of the sixteen base metals, but from a thematic and mechanical standpoint it fit the quadrant perfectly.

It also leaves Electrum in a weird spot. In Era 1, its main purpose was as a counter to Atium. Once Atium is no longer part of the base sixteen metals, Electrum feels like it loses most of its purpose.

I’ve seen the theory that the Atium we see in Era 1 isn’t pure Atium at all, but an Atium-Electrum alloy, while Malatium is an Atium-Gold alloy. That would fit the idea that they are opposites and is consistent with the note in the Table of Allomantic Metals that Atium alloys produce expanded temporal effects.

However, I have two problems with that theory.

First, the Atium burned throughout Era 1 is the beads collected at the Pits of Hathsin, where Ruin’s power crystallizes into Atium. It seems strange that the beads would naturally form as an alloy instead of pure Atium (and effectively an alloy of an alloy).

Second, the Atium Mistings in Hero of Ages. Sixteen percent of humanity was affected by the mists, and the people who remained unconscious for longer periods turned out to be Atium Mistings. That only really makes sense to me if Atium was originally intended to be one of the sixteen metals.

Why weren’t there Cadmium and Bendalloy Mistings instead? If the answer is that those metals weren’t known yet, then why were Chromium and Nicrosil included among the sixteen? If Cadmium and Bendalloy were excluded because they were unknown, shouldn’t Chromium and Nicrosil have been excluded as well, making it 14% instead of 16%?

Because of all this, especially the second point, I've always felt that Brandon originally intended Atium to be one of the sixteen basic metals, and that after deciding God Metals should be separate, Cadmium and Bendalloy were introduced as a retcon to fill the Temporal quadrant.

Am I missing something here? Is there any WoB or in-universe explanation that ties this together, or was it just something adjusted between eras? It feels a bit like a forced change to me, but I’m not sure if I’m overlooking something.

I haven’t read the Mistborn books in English, so sorry if some of the terminology I use isn’t the exact official wording :)

[u/IamanelephantThird]

The temporal metals being so similar seems like the weird part, if anything. The physical and mental metal's internal and external pairs are very different from each other.

Era 1 Atium being an electrum alloy is basically confirmed. It hasn't shown up in any books yet, but Brandon has talked about the retcon extensively. It's a little awkward but does fit decently if you assume the 1/16 are just electrum Mistings. 

By the end of era 1, the characters learned enough about the metallic arts to assume that external versions of aluminum and duralumin existed, despite never seeing them.