Yeah evil heart was what I was thinking about...
Aiki though was terrible. Sure he used 'aiki' to defeat people in ways that defied their understanding... But the story was such a farce. And there were no principles of aiki apparent. It seems as if the author saw aiki once and thought what a cool thing to use for my project without knowing what it really was.
Throw in a lot of crazy violence and sex...and he basically made garbage.
One of my fav manga to date is not aikido based but hajjime ippo which is boxing. And this is because it's very technical and the author must have really understood boxing.
Aiki is seriously such a bad manga. The only thing close related to aikido is the name. The main character literally goes around having sex with every woman in the manga, atleast in the first few chapters. I stopped trying at that point. Mixed in with some redicilously BAD, and I mean BADD action scenes where they attempt at a failed hokuto no ken, it is something nobody should be forced to read.
I did however like evil heart and ippo is well...ippo. You don't get much better than ippo.