Now I know for certain why Isaac Newton is Lucian and not Ekaterina. In the Ekaterina archives there is a small file mentioning John Flamsteed. He and Newton were enemies even in real life. Isaac Newton stal John's work because he wanted to publiceer it under his own name and because John was reluctant to publiceer it.
Rick Riordan knew that if they had been in the same branch they would have worked together, so he placed Isaac on the Lucian because of his sneaky tendencies.
Inside that book was the name of a clue. Later Flamsteed burned a large bunch of his boeken to keep the secret within his branch.

Has anyone noticed that all the Holts are named after someone in American power?

Eisenhower Holt-President Eisenhower
Mary Todd Holt-President Lincon's first lady
Hamilton Holt-President Washington's secrtetary of the treasury
Reagan Holt-President Reagan
Madison Holt-James Madison's first lady
Arnold-Arnold Schwarzenegger

I don't know about u but this seems pretty weird.

Ekat,
Skynite

P.S. sorry about the Isaac Newton Conspiracy, I checked the website and their is no evidence of being Ekaterina. (He should be though. The only thing he did in the government was work at a mint!)