Maki was a previous winner of Battle Royale, by winning in a very smart way. As the time limit was almost up and more than one student alive, all the collars would explode very soon. So Maki used her technical skills to trick out her collar with her issued weapon a pair of tweezers to rip out a wire 5 seconds before all the collars detonated, but hers. When she went to the classroom to go back home as the winner of the Battle Royale, her teacher accused her of cheating and in return she shot her teacher, and like others has run away and was found by Shuya. After reuniting with her parents Shuya told them what happened and her parents and herself joined the Wild Seven. Maki took there places after her parents were murdered as the technical wizard of the Wild Seven and helping Shuya and Yonami recruiting past Battle Royale winners by hacking in the goverment's files of the all the current and recent winners to help them with thier war against adults who made them murder each other and she can track them as they still have the collar on them. Maki is also Shuya's last line of defence.
When the kids are in the Wild seven base a few are killed as they refuse to put down there gun, as the collars of the dead partners are about to detonate Shuya Commands Maki to power up the EMB that over rides the system with no collar contact what so ever although was too late to save one student. Maki de-attaches the collars of the remaining students.
When the goverment sends the army to kill everyone on the island, the participants and younger members escape the soldiers while everyone else stays and gets ready to fight. Maki is the second to last to die in The Wild Seven trying to pleading Shuya to escape. Shuya finally leaves, leaving Saki and Maki the last members of the Wild Seven to face the thousands of soldiers almost breaking all the way through the room Maki feels her wounds sees blood on her hand and looks at Saki in a sad look and then the ATAT Leader shoots her and Saki screaming Maki's name in despair and sorrow.