I've been doing a lot of reading lately, and looking up any grammar points that I'm unsure of as I go. However, I'm utterly stuck at -ていようと. I know －ていようが, but I don't think that's what this is.

Here's the sentence:

もっともそれが分かっていようと、あと数称後には暗黒面の気持ちを真っ正直に声高々と言葉にしていることだろう。

It's looking like ～ようと（も） to me, which is essentially the same as ～ようが. In this case, it'd be something like 'Even if he already knows it, after a few seconds...' (assuming that 称 should be 秒). It's hard to tell without knowing more.

Sometimes a と works almost like と思って; that could also be what's going on here.

Try to "feel" what the sentence wants to tell you.

Mottomo obviously sore ga wakatte iru I knew that... ato suubyougo ni a few seconds later...
The idea is there, right?

I'm not a fan of this kind of thinking (to think in terms of certain grammar patterns), but let's say the pattern here is
A【意志形】+と（して）、B
And "A-you to shite" can be there in place of various things...
"A wo suru tame ni" (Aを目的として、B),
"A-you to shite mo" (Aは無駄),
"A-you to shita/shite ita ga (結局... + 好ましくない結果)"

Javizy's answer is spot-on.