In the end K1-B0 committed suicide by destroying himself along with the entire Ultimate Academy for Gifted Juveniles.
Due to the unexpected outcome of the last trial, where no one casts their votes; Tsumugi and Monokuma were forced to end Danganronpa and K1-B0 was ordered to shut everything down. Since this was an unexpected execution, Tsumugi hadn't prepared a proper one and she trusted the work to K1-B0; to execute herself and Monokuma, which the Ultimate Robot did not hesitate to do since he wanted the killing game to stop and help the remaining survivors.
Launching from the class trial room, K1-B0 immediately shot the entire academy randomly with his upgraded laser. His free will finally allow him to bring down the academy and end the killing game for good.
In the next scene, Tsumugi is in front of the door cosplayed as Junko Enoshima and imitated her infamous hand waving in The Ultimate Punishment in front of the main school's building. However, she took off her cosplay and displayed her sadness and disappointment through her expression, still waving her hands along with Monokuma. Both of them later were crushed to death by a falling rock.
Following the demise of the mastermind and Monokuma, K1-B0 intentionally let Shuichi, Himiko, and Maki survive. After clarifying that the three of them were still alive, K1-B0 smiles before self-destructing himself and flying directly into the wall that surrounded the academy, shattering the glass cage and creating an opening to the outside world.
When the audience from the outside world decided to abandon Danganronpa, this reality show series created by Team Danganronpa will be no more and marked the 53rd Killing Game as the last season of the story.