Jack  

, ジャック

Jack is Jake's son, who was a member of Cross Guard before being killed by Weasel, a chess piece. Despite being clumsy and loud-mouthed, Jack is the weakest member of Team MÄR but not the least resolute. He consistently trains to improve his strength and has an intense crush on every attractive girl he encounters, particularly Snow and Dorothy, despite their harsh treatment towards him. Jack meets Ginta Toramizu early in his adventure when he and Babbo stumble upon his garden. After helping Ginta defeat the Rugelu Brothers, a pair of werewolves seeking to claim Jack's home's vegetables, they become best friends and join Ginta on his journey.