(This is a danmachi idea, I will likely do some ideas for different animes, like I have been doing more Naruto ones recently, but I have a few ideas for this and a few other anime.)
Bell cranel is a energetic boy, being raised in a very rural area with no other towns or anything for miles.
He is raised by his aunt Alfia, uncle Zald, and grandparents (Zeus and Hera). While growing up, they all trained bell to be an amazing adventurer, although his grandmother and aunt were reluctant to let him.
Bell is trained to use multiple different weapons from his uncle, as well as being taught how to cook and to develop his body by his uncle.
His aunt taught him magic, and Alfia along with Hera taught him how to be a gentleman, and how to treat women.
Meanwhile Zeus, helped him with some magic and ideas in how to use it, as bell had both sound magic like his aunt, and fire magic, like his father. The difference between his father's fire and bells, is that he had a few healing spells with the fire magic, called phoenix's flame.
Bell goes to orario when he is 10, earlier then his aunt uncle and grandparents, and joins the miach familia.
Bell will have a harem, cause it's bell, a harem magnet. (Will get it when he grows a bit, I recommended having a major event after a little bit of the story, and having a time skip after he had to be away for a while or something like that.
He will be skilled and will get his skill liaris freese.
Bell will be as innocent as canon, and more so as he is still young.