Talon was tasked by Marcus Du Couteau to look after his house in his absence, and after training him he disappeared. Katarina is known to be reckless and quick to make rash decisions, because it's her style of fighting. Talon is there to loosely watch over her especially, which was probably the reason why he was trained by the General for a few years before Swain took power. he qasMarcus Du Couteau was the person in question between Swain and Leblanc since he was the one person who was aristocratic but also problematic for Swain. Swain dared not remove Marcus from power through conditional means, but had to eliminate him because of his previous loyalty to Darkwill and overall secrecy. A good tactician makes sure there are no unknown variables.
Marcus Du Couteau may have possibly gone into hiding to uncover more about Swain because this sudden change in leadership may prove problematic for him, since he has knowledge of Darkwill's dealings and dabblings into necromancy. Now that Swain owns those secrets, Du Couteau needs to observe what is done with those secrets. Should Swain make a move on his house in his absence, he would expose himself publically as a usurper of power and lose public opinion, possibly being overthrown. Also, Swain himself would be vulnerable, leaving many things to Marcus Du Couteau's mercy. It was a smart move, and Swain knows it, so he's biding his time. Darius asked for nothing but a strong Noxus united under a leader, but he was hesitant because Darius isn't the most able or willing to delve into politics. When Swain emerged, Darius saw much promise in this man, as he was the ideal Noxian vision: Strong, fearless, and tactically superior.
Cassiopeia acted alone in seeking out Shurima, as she was just power-hungry. She never had a knack for hacking and slashing like her sister Katarina, and wealth was just a means to an end. Swain and House Du Couteau are individual entities: neither with the other.
The Leblanc/Swain deal was that Swain and Leblanc staged a battle in Kalamanda, with Leblanc posing as the crown prince himself. Nobody really knows why, but I suppose it was an attempt to get Demacia's attention in order to plant his spies in Demacia without any suspicion. Either that, or he planned to reconcile with Demacia and make a treaty in order to remove Demacia from the equation so he wouldn't face much resistance in his scheme.
Urgot is a man-made soldier, most likely used as a first-line defense of Noxus, seeing little use in battle and more as a fear factor. He is an avid fighter, using technology to do what he is told, but in general he isn't used often other than to deal with spies and assassins.
Draven is Noxus' executioner, and he takes pride in it. However, should the need ever arise, his unique style of axe throwing could be used as a long range destructive force in battle. He doesn't see much real battle, however, so he isn't exactly the best option. Regardless, he is experienced in fighting. Politically, Draven doesn't involve himself much unless it would involve himself. If Darius asks for his help (if that happens), Draven would most likely answer the call out of respect for his brother. He's a deadly force but one that is difficult to enlist the aid of, so he's left to his own egocentric devices.
Sion is a tool of war. He cares not for politics or allegiances. He is a creature made for war, the soul furnace powering him requiring more and more death to power it. Swain only would see it fit to release Sion should the need arise. He would most likely command his troops to fall back before releasing his behemoth of a weapon to endlessly carve a path of destruction through the enemy. He is merely the secret weapon of Noxus, and even Darius finds his existence a little unsettling. Only Swain knows how to contain Sion, and has him follow him around like a pet, showcasing his creation as a warning to all: mess with Noxus and you face the consequences.
Hope I cleared some things up.
