Middle school student Tsuna has always gone through life in last place; but when he learns that he is getting a tutor to help him raise his game, he had no idea that his benefactor would turn out to be... an infant and a mafia hitman?! As if things can't get much stranger, Tsuna then discovers that the powerful Vongola family has chosen him to be its next successor - a position that has control over all mafia families. Joined by friends Tsuna unwillingly starts out on his path to becoming a mafia boss - if he can survive the training!
Shirihama Kenichi is a weak scaredy-cat, and his status as the karate club's punching bag has earned him the name of ‘Weak Legs'. One day Kenichi meets Miu and, impressed by her skill after she effortlessly throws him to the ground, he follows her to the Ryouzanpaku dojo. There he finds five great masters of martial arts, and driven by his desire to become stronger, he begs them to accept him as their student - though it won't be easy. Kenichi endures harsh training (and injury) from Akisame - the philosophizing Jujitsu master; Apachai - the Muay Thai ‘God of Death'; Kensei - the ecchi Chinese Kempo Master; and Shigure - the weapons prodigy. Finally after proving his determination, he is accepted by Shio - the 100-dan Karate Master, who had initially wanted nothing to do with him. Now Kenichi walks the long and arduous path to becoming a master himself, all whilst trying to protect those he cares about from anyone who would dare to harm them.
Kenichi and Reborn! both star incredibly timid and weak high school boys. Both Tsuna and Kenichi also are motivated by their feelings for their friends and especially the girl they like. The battles get more extreme as each series progresses and the comedic nature stays strong throughout the series.
Gon Freaks is a young boy who lives peacefully on a rural island, until one day a mysterious man who calls himself a hunter brings him news that his father is still alive, and is also the greatest hunter of all time. With this new information, Gon is now determined to become a hunter and find his long lost father. First, however, he must pass the hunter exam, where he will make new friends to help him in his adventure.
Hunter x Hunter and Reborn! both have a unique style of fighting. They both begin with regular fist fights, but as the series progresses the fights get more extreme by using Ren or Dying Will respectively. Each character has his own unique weopon and grows stronger as the shows progress.
Both of those shounen battle mangas start with almost identical setting. The main hero is a weak, bullied and cowardly kid who suddenly learns, about his amazing lineage and mysterious power he can inherit ( mafia family Vongola in Hitman Reborn, strongest magical king in Hyde and Closer).
Due to this sudden development many assasisns targets young boys live. To keep him alive he receives a guardian in childish body (Teddybear Hyde in Hyde and closer and child Reborn in Hitman Reborn). This guardian, despite his appearance, is powerful being and skilled teacher, who will direct young boy towards his powers.