The moment that I realized that the anime I found most comparable to To Aru Majutsu no Index while watching it was Bakemonogatari, I knew that people were going to look at me funny if I told them that without explaining myself, and sure enough, they did. Therefore, I’m explaining myself. I’m going to do this in the form of a compare and contrast – I will take each key element of the storytelling in these shows and then prattle on about how each series is alike (or different) in that regard.
Main Character
Starting with the central element of either story, the male lead. Ordinarily, it would be no surprise to find similarities in the male leads of two anime, seeing as most of them are pretty generic, however the leads in these two shows are more alike in their abnormality. In both stories, the main character is an extremely nice guy with a penchant for helping people, but doing so in a largely nonchalant way. Both of them have strong moral bases, but seem to find the fact that they have to help people all the time troublesome. Araragi often wonders how he got himself surrounded by such strange people and events, and Touma has pretty much gotten used to a life where stuff like this is always happening (to where he’s developed the catchphrase ‘Fukou da!’ meaning ‘such misfortune!’).
However, in spite of both of them having constant pains in the ass, neither ever believes that there is a reason not to help someone. They both jump right into danger without even a second thought to how strange it might be to help a person in these situations, and they quickly get themselves very involved. The female characters closest to them in both stories often make fun of the guys for always saving various beautiful women, and many consider it a fault of theirs. Nevertheless, it is quite clear that both leads are bound to involve themselves in much future danger and help many more people, regardless of negative consequences on their personal lives, just because they are compelled to do so.
Perhaps what sets these two apart the most, though, is that both of them are far from normal people, and in fact may be one of the strongest forces in the stories they belong to. Past events have made Araragi into a part-vampire, granting him some supernatural abilities, and his experiences have acquired him a network of people who can help in all sorts of weird situations. Meanwhile, Touma was born with an incredible power like no other that makes him a valuable force, and as he gets into more situations thanks to his natural desire to get involved, he builds more and more connections until rumors begin to spread about a ‘Touma faction’ made up of the various people with emotional debt to him. Furthermore, thanks to losing his memories at the end of the first arc (book 1, ep 6), Touma believes himself to possibly be a person who has always been involved in these strange situations, which makes him, like Araragi, more accepting and understanding of unnatural situations.
Araragi is certainly the more attractive of the two. Art by something-4570 http://gelbooru.com/index.php?page=post&s=list&tags=something-4570_(pixiv)
My Sword Is Unbelievably Dull 