|Use in-game||Murder Weapon|
|Used by||Celestia Ludenberg / Hifumi Yamada|
|Used on||Kiyotaka Ishimaru / Hifumi Yamada|
The Justice Hammer is a weapon used in the game Danganronpa: Trigger Happy Havoc. There are four hammers that are used to attack 3 students in Hope's Peak Academy - Celestia Ludenberg, Hifumi Yamada and Kiyotaka Ishimaru. The attacks left Hifumi Yamada, who was struck twice, and Kiyotaka Ishimaru dead.
After Hifumi and Kiyotaka had been found deceased, the team noticed that one of the students had been missing all of this time, Yasuhiro Hagakure. Yasuhiro was later found unconscious in the pool's locker. He was blamed for the murder of both of the students and the attack on Celestia. However, something did not quite add up with the suit. It only fitted Yasuhiro, but he could not bend down in the suit, making moving both of the bodies to the Art Room an impossible task. This aroused Makoto's suspicion and Yasuhiro was cleared of being the murderer, declaring him as a victim of the crime since he was knocked unconscious and used as a red herring.
Later on in the class trial, it was revealed that Celestia had tricked Hifumi into killing Kiyotaka by saying Kiyotaka stole Alter Ego and was plotting to kill Hifumi. They drew out plans for Hifumi to kill Kiyotaka and Celestia to kill someone else so they could both escape the academy. Celestia only had plans to kill one other student, Hifumi Yamada. Hifumi struck Kiyotaka with Justice Hammer #3 whilst Celestia struck Hifumi with Justice Hammer #4. Celestia was later executed in the trial, declaring the only reason why she plotted the murder was for the money. She drew out the blueprints for Yasuhiro's Robot Justice suit.
 Celestia Ludenberg's Attack
Celestia was struck with Justice Hammer #1. She was found, supposedly, waking up from unconscious in the Recreation Room by Makoto Naegi. She reported that she had been attacked by somebody in a Robot Justice suit. She took a picture of the person in the Robot Justice suit taking Hifumi away.
During the Class Trial, this theory was dismissed, as it was made clear that Celestia had not been attacked. She had attacked Hifumi Yamada with Justice Hammer #4, killing him after manipulating him to murder Kiyotaka.
 Hifumi Yamada's Attack
Hifumi was first "attacked" by Justice Hammer #2 by the person in the Robot Justice Suit in the Nurse's Room. This was a lie, found out in Chapter 3's Class Trial. Hifumi had tricked the fellow students by pouring transfusion blood over his face and Justice Hammer #2.
He was really killed by Celestia Ludenberg with Justice Hammer #4 later on in the game. Hifumi died in Aoi's arms, whispering "Yasuhiro" before his death. Celestia said that Hifumi's attacker was obviously Yasuhiro Hagakure, but when Makoto Naegi realised that nobody knows Celestia's surname and asked her for her eHandbook, she was hesitant and refused to hand it over. When she finally did, her real name was confirmed as "Taeko Yasuhiro", sealing her execution fate.
 Kiyotaka Ishimaru's Attack
Kiyotaka was attacked with Justice Hammer #3 by Hifumi Yamada. Hifumi was manipulated by Celestia into killing him by saying that Kiyotaka was out to kill Hifumi.