Hitoru Wakanabe embodies everything about Japan (that I enjoy from various parts of Pop Culture). A kaiju fighter with a penchant for rock music and “gate ball”, the Japanese equivalent of Croquet.
The Uchide no Kouzuichi is from a slightly different part of Japanese culture, a mythological folktale of the One Inch Hero, who uses the hammer to grow to normal size. Hitoru, as a normal sized person would therefore use it to grow to normal size and fight giant monsters, Ultraman style.
The Uchide no Kouzuichi was purported to have a whole suite of deus ex machina powerful abilities, but mostly the mallet imbued great luck. So Hitoru has the uncanny ability to ricochet his ball just right to bounce his way to Croquet victory. His special ability allows him to choose from a few different trajectory options when his ball collides with an opposing piece. Giving him more control over an element of the game that is a randomizing element for the other players.