Regarding Solus:

It's very interesting that Solus is so eccentric. I wonder if he acted that way in public when he was in power? He was, after all, beloved by his people. We also know that he commissioned the Prima Vista and supported the arts, which was used as method of bashing Varis. Yet now we know that Varis is actually the one who truly cares for his people whereas Solus outright calls them 'powerful pawns'. I do find myself curious as to how far the writers will take the similarities towards Ardyn. FFXV ended up becoming very dark when it came to that particular character and his actions. FFXV also did very well for itself so I don't doubt that we'll get major references to it at some point...albeit with twists unique to FFXIV.

Solus also states outright that Varis regrets knowing the truth about the Empire. It'll be interesting to find out when, exactly, he came to know of Solus' true nature. Was it before or after the War of Succession? Speaking of that, it seems likely that no matter who won they would have found themselves in the same situation as Varis. I'm still hoping we get further clarification in regards to the situation with Regula. Now that he's dead, it serves to further isolate Varis. He has nobody to lean upon, to our knowledge. Even his personal guard are easily manipulated to do Elidibus' bidding. With that said, when Varis shoots Solus the guards behind him appear to be genuinely shocked by the proceedings.