First thing I'm looking for: So this is pretty simple: characters who are strategic geniuses. Chessmasters. Light Yagami, Akagi, David Xanatos, Lord Vetinari. You get the idea.
However, I'd like the series to have some depth to it, too, so "strategic genius" isn't just an informed attribute, the way it is in that one Death-Note-ripoff where the guy hypnotizes people. Like I'm looking for Batman levels of crazy-prepared and planning ahead here.
One thing that appeals to me about Light is that his strategic mind doesn't stop at the Death Note: he's so hard to catch for a reason. He's not one of those dudes that stops being brilliant just in one realm; it carries over into his life.
Second thing I'm looking for: Manga that actually -show- scarily-intelligent characters
In comics/manga, it's easy to portray smarts in the same way people portray strength or "power levels": someone says "Whoa, Professor Chaos! His IQ is OVER 9000!" But anyone who's read a lot of fight mangas knows, it's easy to say a character is tough, it's harder to show that he is. What I'm looking for are mangas where you've gone, "holy shit, that character is smart." This usually because the creator has -shown- us the character is smart, not just told us.
Let me use Death Note and Akagi as examples here. In Death Note, we're told Light's the number one student in Japan and his sister refers to him as a genius. But that really hit home when
Spoiler (mouse over to view)
we see the lengths to which Light has gone to use the Note, how he's filled it out; how he's actually applying time management to writing in the Note; how he rigs up his desk drawer to explode if it's opened the wrong way. And all of this is before the -really- big battle of wits begins!
By contrast, in Akagi, none of the characters tells us the lead is a genius (though the narrator does.) We get a sense of it, though, when
Spoiler (mouse over to view)
Akagi has a confrontation with those three guys his own age and outfoxes them
or when Spoiler (mouse over to view)
Akagi and that blind dude are having a pissing contest with the gun, and the blind due says, "You counted how many times the barrel turned, didn't you? You never bet. Neither do I."
That's what I'm looking for. Series where the creators do the work in showing us insanely smart people.