Mathias Caltagirone, better known by his ring name MBM, is a Belgian professional wrestler who made his in-ring debut in 2016 for the Belgian Catch Wrestling Federation and has competed across various independent promotions, becoming a one-time NFW European Champion, two-time CACC Supreme Champion, one-time LDN Capital Wrestling Champion, two-time XTC Hardcore Champion, and one-time Superstar Wrestling Hainaut Champion. He also achieved major success in the tag team division alongside Ultima Sombra as Rivality, becoming a one-time WPE Tag Team Champion, one-time CZW Tag Team Champion, two-time APC Tag Team Champion, one-time BCW Tag Team Champion, two-time CACC Tag Team Champion, and two-time WrestlingKULT Tag Team Champion.