It ran in Grand Jump and later on Shōnen Jump+ .
Written by HiRock and illustrated by Shinya Komi, the manga began in 2015 as a remake of Komi’s earlier work, Ex-Vita . Ex-Arm
Set in a cyberpunk future (2030), it follows high schooler Akira Natsume, whose brain is saved after a fatal accident and turned into a highly advanced superweapon called an "EX-ARM". It ran in Grand Jump and later on Shōnen Jump+
The 2021 anime adaptation by the studio Visual Flight is where the franchise’s reputation shifted dramatically. Ex-Arm (TV Series 2021) - IMDb it follows high schooler Akira Natsume