Shinon was a real barrel of fun, especially the part where he gets drunk off his ass and insults Ike to his face over the latter being knighted and made the leader of Crimea's army, including mocking Ike's relationship with Elincia, asserting that Ike was going to throw the Greil Mercenaries away now that he had professional soldiers under his command, and demanding that he change the name of the Company because Shinon still considered Ike an unworthy successor. Really solidifies his character as a bitter man who knows he's replaceable and lets the rest of the world know just how much they piss him off. Of course, then you have his relationship with Rolf, where Shinon trains the kid free of charge just for the chance that the apprentice may surpass the master.