AIKI is a Seinen action manga, written and drawn by Isutoshi, an artist mostly known for doing H-manga. However, as the series has progressed, the manga has tilted more towards martial arts and comedy and less towards the ecchi side (though a good amount of Fanservice still remains).The story features Kunitoshi Joukyuu, a young martial artist who is so strong that his father/teacher actually dislocated (and then relocated) all of his joints within one night just so he would only be able to access half of his power, in an attempt to teach him either humility or creativity. Even so, he constantly wipes the floor with the competition, to the point where a couple of muscular female teachers beg him to train their "mistress": a small, raven-haired girl named Kizuki . While Kizuki knows a decent amount of Aikido on her own, she's the granddaughter of the chairman of the school board and a high-value target because of the school's politics.Of course, it doesn't help that most of Juzenji High School is out to defeat Kizuki, or that Kunitoshi's scantily-clad, female cousin Miu Takatori(who's the principal's daughter and Kizuki's main opponent for control of the school) is trying to recruit him by any means necessary. Not to mention that Kunitoshi himself is a Jerk Asspervert who constantly arranges for his students to be thrown into dangerous situations and may be the worst role model ever. Despite all this, Kunitoshi grudgingly trains a growing group of women into skilled martial artists while battling a Sorting Algorithm of Evil as he looks for a way to regain his previous strength.In short, think of AIKI as a much more lewd and evil version of Kenichi: The Mightiest Disciple.Gained a sequel called Aiki S which is currently in publication.
Action Girl: Any girl with a name in the story, and even some without them.
Amazonian Beauty: Houmei is extremely muscular at the start of the manga, such that it actually slows her down in fights and she has to slim down a little bit to be effective. Kageyasu's no slouch in this department either, with a nice set of washboard abs and biceps.
Author Tract: The sheer weary one-sided contempt and amoral cynicism pouring out of Isutoshi these days is pretty staggering. Before that TendeFreeze and even Slut Girl were comparatively lighthearted and optimistic, with the only real author tracts being the Fanservice, the uncommonly beautiful female designs, some tongue-in-cheek sarcasm, and strong influence from assorted 1990s fighting video games.
Badass Grandpa: Kaneoto Houju. Due to old age, he has only about a tenth of Kunitoshi's speed and lacks the stamina to fight for more than 30 seconds, as well as rheumatism and cataracts. He still manages to fight Kunitoshi to a draw. Arguably the most skilled character to appear in the original manga.
Brought Down to Normal: Well, to at least half his power. Kunitoshi still manages to beat almost everyone without breaking a sweat.
Charlie Brown from Outta Town: Akemi's boyfriend Daiki's going off the deep end, and Kunitoshi's the only one who might be able to stop him — if he can get back into condition. He needs a sparring partner at his level, but Akemi doesn't think she can actively oppose Daiki. In the nick of time, the mysterious masked wrestler "Joan the Shadow" appears. (See Paper-Thin Disguise).
Combat Pragmatist: Kunitoshi, and he tries to teach his students to be ready for this.
Figure It Out Yourself: Kunitoshi never properly teaches his students, even when he's a college lecturer. However, he does give legitimate praise and guidance when his students do learn.
Finger Poke of Doom: With 90% of his strength in his left arm, Kunitoshi is able to take out two members of an elite military martial arts squad by poking their foreheads.
Flash Step: Being able to move faster than the eye follows is a sign that you're one of the stronger characters. On video, it looks like a stupid dance, but Kizuki learned to pull it off by mimicking the dance, earning some respect from Kunitoshi.
Kunitoshi: Power should just be the icing on the cake. If you utilize your opponent's power, even a little kid should be able to send a two-meter-tall wrestler flying. It's not easy, but it can be done... It's not power, nor is it speed.
"''Frieennds? So you're that kind of guy? Always singing the same old song. 'You're not alone.' 'If you have troubles we will be there for you.' 'Together we are strong.' Those kinds of songs, there are so many of them! (...) However... don't you think they say that just to cover their own incompetence? Isn't that just a means to cheer oneself for being poor and hopeless? 'Friends' is what you call someone who likes to be someone else's minion, isn't it? I don't need such things like 'friends'! Well, I don't have any friends to begin with!"note Full disclosure — he's saying this to the new Big Bad's new Quirky Miniboss Squad to get their goat while deliberately giving his students a preview of what they'll be up against.
Handicapped Badass: Kunitoshi can only usually tap into half of his full strength ever since his father dislocated and relocated half of the bones in his body in a vain effort to humble him. He regains part of his ability as the series progresses, but Kunitoshi himself believes he will never fully recover.
Houju has rheumatism (pain/inflammation of joints/muscles) and cataracts (causes blurred vision) in addition to reduced physical speed and stamina from old age. He's still one of the strongest characters in the cast.
Karasumaru temporarily became this as a result injuries inflicted during his fight with Joukyuu, dropping under 50% of his former ability. He himself notes the irony that his condition is so similar to Joukyuu's. Both he and Joukyuu note he will recover in a few years.
Hollywood Healing: Whether they've taken a whip to the face, a large punch to the stomach, had a hand penetrated by a sharp object or breathed in poisonous gas, bandages heal everything.
"Geez, has my place become a field hospital?"
I Am Not Left-Handed: Karasumaru's battle with Joukyuu is pretty much entirely going his way... until Joukyuu reveals that just because he's recovered to 70% of his old strength, it doesn't mean he's limited to 70%. Cue beatdown.
Though in fairness the person did offer it up if he won the fight. Naturally he didn't waste any time beating her.
Improbable Weapon User: Eventually this becomes more of a rule than an exception, from bizarrely shaped multi-bladed swords to circular three barreled guns and even more indescribable weapons. It seems that for many modern martial artists, getting an edge means developing a signature style too weird to be predictable.
Slasher Smile: Isutoshi appears to have a lot of fun drawing these.
Smug Super: The only reason Kunitoshi gets away with being such a cocky bastard is that he has the skills to back it up.
Take That: During the fight between Houmei and Seiji Sawatari, Seiji breaks out his "Cat Fist". Kunitoshi's reaction...
Kunitoshi: I know that the Chinese martial arts have 4000 years of history, but doesn't "Cat Fist" just sound too weird?
That Came Out Wrong: Seiji Sawatari (the Chinese Kempo fighter who humiliates Houmei) has a tendency for his expressions of bloodlust to come out the wrong way. For instance, when trying to challenge Kunitoshi:
Seiji: I'm here to screw with Joukyuu-san. Kunitoshi: (Grimaces) Seiji: Hold it right there, I'm not a homo... Kunitoshi: Go kill yourself.
The Starscream: Habu became disgruntled with Daiki and in chapter 40 of the manga revealed her intention to take control from him. She didn't get the chance to act on it.
Andrew, the Super Soldier who was engineered to be a superstrong Lightning Bruiser that feels no pain who is doomed to die young thanks to the side effects of the experiments performed on him. Even Kunitoshi feels a little sorry for him.
What the Hell, Hero?: Everyone else in the series calls Kunitoshi out on his, well, everything, all the time. He never listens. When Bull-kun tries it in chapter 77, Kunitoshi turns it back on him by making him realize that he isn't any different.
When You Snatch the Pebble: Kunitoshi challenges Kizuki to catch a small fish — with one hand, slowly — to prove that she's worth his time.