Recollection of Heavy Metal
Diamond & Club Side Story: Recollection of Heavy Metal (追憶のヘヴィメタル(ダイヤ&クラブ外伝)Tsuioku no Hevimetaru(Daiya & Kurabu Gaiden)) is a one-shot manga. It was published in the February 2013 issue of Monthly Comic Zenon.
Plot
This story is a spinoff prequel to the original Fist of the North Star by Buronson and Tetsuo Hara, and covers the events of Diamond & Club's lives prior to their appearance in the manga.