The Sovereign

I am completely on board with you on all of that. I also suspected we would see Li Markuth again and then was basically sure of it when the mentioned the prison break in the earlier chapters. It was cool though to get an idea of how powerful he actually was since Foundation Lindon and Suriel weren't the best of litmus tests... I found it pretty interesting that he was actually more powerful than Monarchs so without Suriel's initial intervention he might of actually succeeded in his original attempt. 

I think my favorite part of the book was Dross bullying Northstrider's Codex.

The funniest part about the whole Markuth thing is that he didn't even ascend under his own power, he hitched a ride with someone else and then he tried to come back and hype himself up while relying another Iteration's energy system to fill in the gaps. But yeah he deserved it.
Dross haunting the Codex was hilarious, but I have to give the spot of favorite moment to Fisher Gesha yelling about Lindon over the teleport thing.