Eyeshield 21, Katekyo Hitman Reborn! Recommendations
the main characters start out very similar both very weak willed and give up easy, the story's although very different bring about change to them and along with the help of some brilliant supporting characters they find out they are far stronger then they first thought.
The main character are very similar scared and very protective the do anything to protect the ones they love.
The build up and changes and problems faced in story allow the character to develop and in that sense this story is very similar.
Both series have a hapless loser protagonist who becomes part of a group initially against his will and in doing so forms bonds and grows as a person. Together they face increasingly formidable opponents as the series increases in seriousness and intensity, with themes of teamwork, friendship, and hard work become becoming major elements. Although the overall subjects of the series are different, the structure, character types, and themes are remarkably similar.
It's really difficult not to make parallels between Eyeshield 21 and Katekyo Hitman Reborn. For me, at least. The protagonists are quite similar: Dame Tsuna who doesn't display tremendous skill for anything, but has a big heart and Sena, and often bullied high school student also with a big heart. Both manga deal with the growth and maturation of the main character whilst making great friends on the way. Tsuna and Sena also look quite similar. Though the universes both deal with are vastly different and some themes vary, there's a very similar large underlying. Both series are fun to read and have memorable characters.