Originally Posted by
Nik Hasta
Part of this is the whole spiritual angle of "being a Great General of the Heavens," which isn't... fully Rumbles viable but it's a factor.
Houken is purified martial might, he only fights with his own strength and is therefore held up by only his own willpower. Shin, Ouki, Duke Hyou and others are Great Generals and are therefore held up by their comrades and their combined spirit. This contributes to the weight of their blows to make them stronger than they should be, especially in duels.
This is first shown when Ouki, having been shot in the back by one of the Ten Bows and then impaled right through his midsection by Houken has an exchange that basically goes;
Ouki: "Bitch, you think this is enough to kill me? Me and boys are gonna roll on out of here, I will just need to cut down Ouki real quick,"
*swings slowly because he has several enormous holes in his torso*
Houken: "this is asinine, you are already dead," *catches glaive by the shaft in his hand*
Ouki: "Oh am I?"
Houken: *finds he cannot stop Ouki from swinging despite all of the aforementioned big holes and blood loss* "What...?! This is literally impossible,"
Ouki: "Great General bitch, I don't have to care about the rules,"
So, Shin gets to the point where he is, technically, more than just a man. He is a Great General now which means he hits harder and is supported by the spirits of his men both living and dead. There's some ambiguity as to how literal this is in the setting but, given that Houken has feats and abilities that make him seem like he wandered in from a different manga with different rules, this feels like an appropriate counter-balance.
Also, also, in extreme enough circumstances, Shin can do the whole solo small armies bit (kind of). At the Siege of Sai, Shin goes all out on the penultimate day and slaughters dozens, if not hundreds of men as they swarm the walls of the city. He has his men with him but they are like "we actually can't get near him and more the half the dead people on the floor from this day's fighting are courtesy of Shin,"
This, again, basically wiped him out to do so. Houken does it way more easily and more often by Shin, as discussed, can just about reach that level with his peak performances.