These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Author Appeal: Apparently, Naosuke really, really liked the naginata, as he said that he wanted to turn Maki Baian, the first enemy encountered, into a recurring character. So, it's not surprise that the strongest of Jinsuke's bodyguard is a naginata master who trained Baian and comes close to killing the main character (and survives).
Ryugo Daimaru, heir of the Daimaru, is obsessed with the ascendance of the family- or more accurately himself. To that end, Ryugo has cultivated the talent of his mentally unhinged younger brother Sakon who is known as the strongest in the school's history. When Sakon was young, Ryugo threw him into a basement with multiple other prisoners with the promise only one man would be allowed to leave after the others were dead. When a berserk Sakon emerged, Ryugo directed him to kill their father who he determined as worthless. Ryugo uses Sakon's violent side to destroy all those who stand in his way and when Gamaran fights Sakon, Ryugo rants how Sakon isn't allowed to lose because of how perfect Ryugo made him.
Jinsuke Kurogane, the mightiest sword in the world and the most wicked. Jinsuke joined the Ogame School, only to later give its leaders the ultimatum of joining with him to conquer the world or die if they refused. When they showed their reluctance, Jinsuke slaughtered the school with his followers, including the friends of his son Gama in front of Gama's eyes, before defeating Gama as well and only sparing him on a whim. Jinsuke shows no hesitance in an attempt to kill Gama later and no remorse in killing his own students should he decide to. He manipulates the Washitzu clan by holding the mother of its new Daimyo captive with her life on the line and builds a power base where he plans to create a world where he, the strongest rules, and any who oppose him fall to his sword. In the end, when asked if he has any regrets, he declares he has not even one.
Fridge Brilliance: At first, the fact that there are 31 schools in the first turn and Gama's group consist of 4 schools seems a terrible mathematic failure... then you can realize that it's perfectly possible if all the other groups are composed of 3 schools each and the one containing Naoyoshi, who's The Unfavourite, so they wanted to increases the chances of his defeat. Furthermore, Jinsuke was behind the whole thing, meaning that he wanted to test Gama's skills.
Ho Yay: Considering that there're only two or three major female characters, this is inevitable.
Gary Stu: Iori is even worse, he dominates each individual fight he's in.
Moral Event Horizon: Mario crosses it, not only admitting he killed his Muhyo allies for political gain, but later has his men ambush Kai, showing he doesn't even have the same honor of a warrior that even a depraved Blood Knight like Muraku had.
Nightmare Fuel: Sasuke, when he gets seriously into a fight. The fact that his spear can behead, maim and rip hearts out only add fuel to the fire.
After taking the first two Juugan pills, Ryuuhou turns into an unstoppable brute with red eyes and enormous force, who jumps into the fray by ''crushing" one of his surviving underlings. Then, he takes the injection, gaining Dissonant Serenity as his eyes bleed out.
MurakuMatsumoto during the whole second fight against Gama. Picture this: you're fighting an insane, sadistic bastard armed with long chains tipped with iron weights capable of turning your brains into pudding anytime. He's wearing a mail made from the hair of all the guys he "loved" and killed before they grew too old and if you lose you're going to be "added" to it. Even after getting seemingly killed by a sword in the gut, he still stands up again in his worse Limp and Livid performance babbling about how Gama must "become one with him now". Eeeeek!