My current pet theory is that he’s researching the origins of aberrants and the cataclysm, which are one in the same.
Basically I’m guessing that prior to the cataclysm when break events happened, people didn’t become aberrants, they became titans (or were put on a perilous path towards becoming titans if they could maintain enough control).
This explains why all the titans gradually went mad and died out post-cataclysm, but also why there don’t seem to be any powerful pre-cataclysm aberrants still around, since I doubt that aberrants would age, and they’re very hard to kill.
Within this theory, pre-cataclysm titans were kinda like vampires in that they would keep their minds, gain power, and and become essentially immortal, but also be cursed with insatiable, destructive hunger that colored all of their experiences from that point on and made them either an outright threat to humanity or a ruling class over humanity that leveraged their strength to have their demands met.
Then the cataclysm was either an attempt by them to free them of their hunger (manipulating the laws of the universe such that magic itself supplied infinite power to those who broke, rather than forcing them to constantly consume matter) or an attempt by ordinary people to free themselves of these insatiable, magically powerful giants (manipulating the laws of the universe such that those that go through break events don’t retain their minds and are unable to guide their forms).
And then, if that is true, Lacer would be researching the cataclysm in order to find out how to literally abruptly reshape the laws of magic. it would be why he knows so many pre-cataclysm languages as well as ones from the immediate post-cataclysm period and why he is such an expert in Titanic history and lore that he surpasses professors who specifically dedicate themselves to that field, but also maintains an active interest in aberrants and those who might safely be able to cast through their own bodies (the Nought bloodline).
He thinks that the Nought bloodline surviving changes everything, and also that he would love to use the Raven Queen as a test subject if it wouldn’t be so dangerous because he thinks that the Noughts might be able to retain their sanity during break events and still become modern titans.
Any research on this subject would, of course, violate his Red Guard oaths, since the knowledge would be inherently dangerous to humanity, but he wouldn’t let a little thing like that stop him.