"Birds are dying.. flowers are wilting.. on days like these people like you should be dying with them..."
– Justice!Sans 2017
Justice!Sans brings justice to all wrong doers, he can create portals to any AU or timeline. He is a godlike being and upon death he will reset his enemies LV and Gold to 1 and prevent them from ever hurting anyone ever again. Justice!Sans brings justice and never rests, after his death he will be revived after 20 days. The only people that stand a chance against him are Error, Reaper and Ink. Justice was created at the beginning of time to make sure everything is how it needs to be, he didn't create AUs because that's Ink's job.
Justice!Sans is kind and will heal people who do the right things, however with a murderer or an unkind person he will do the opposite, he will make them feel the pain that he or she inflicted on others. Overall Sans has two sides of him, the kind side and the not so kind side. He will show no mercy to evil creatures, even the ones who are tortured. He strongly believes that if someone is being tortured they have been horrible in their past life and deserve it.
Most of Justice's clothes are coloured yellow to symbolize justice just like the yellow soul of justice. The black means hatred, hatred towards sinners and wrong-doers. His eye always glows yellow because he likes to show that he is powerful and can keep his eye glowing even when not in battle, a bit like Underfell Sans. He has a very fluffy black and yellow hood, sometimes Nightmare is jealous because Justice isn't just a black blob like him.
Justice!Sans' attacks will heal the enemy if they are good, if they are evil it will leave them at 0.1 HP or right out kill them. Sans can summon gaster blasters and bones and use attacks of everyone their enemy has killed. He can see everything that is happening in every AU and timeline just like Core!Frisk. If a nice person tries to harm him their LV will instantly be increased to 20 or higher making it easier for him to kill the person that hurt him. He can also use telekinesis and summon blue and orange gaster blasters. Only Error managed to escape Justice's power and the rest who faced him died.
Weakness 1: If Justice hurts or kills an innocent person justice itself will erase him from existence for an eternity
Weakness 2: Error, Ink, Reaper and other powerful Sanses like him can kill him for 20 days
Weakness 3: Humans have the ability to take Justice!Sans down, but not for long as he will return after a couple of months
Weakness 4: It is possible to dodge all of his attacks, but it is nearly impossible. Only a Sans could defeat him but even then it is very hard
Legends say that Justice was born from when the first genocide route was committed, he was only a small piece of dust that floated around. The reason for this is because he was made of the dust of UT Sans, each time a Sans died he earned one piece of dust. At one point he was just a head and floating shorts, after many deaths of Sans-es he became the skeleton he is, except he was EXTREMELY weak. So he waited more and soon he began to have 1 attack and 1 defense just like any other Sans, but it didn't stop there. As more Sans-es died his attack and defense increased, he finally had 99 attack and 99 defense. Justice soon realized how many Sans-es died for him and he had the power of every Sans that died, he was going to avenge them. Justice at first began to punish Frisk, Chara etc. but soon he noticed how other people died and he also punished the people who murdered. (Even though he murders as well. That's kinda hypocritical).
Error!Sans - Error and Justice are enemies and they usually avoid each other because they both know that if Error kills him he will be killed himself by either Reaper or Ink as they are friends.
Ink!Sans - Ink and Justice are friends, however because of so many evil monsters and humans Justice rarely sees him because of his job
Reaper!Sans - Reaper and Justice work with each other because they both bring justice to wrong-doers and have similar goals, Reaper usually lets Justice kill the tougher enemies
Underswap!Papyrus - Justice doesn't really like Papyrus because he refuses to believe him, even though he can see everything that's going on in the multiverse. Papyrus refuses to believe in timelines where Blueberry is evil or dead even though he knows that timelines like that exist.
UT Sans - Undertale Sans and Justice are pals because Justice granted him the power of karmic retribution. Justice usually whispers predictions to Sans when nobody is around so that Sans would be aware of important events and so that he could protect his Papyrus from danger.
Nightmare!Sans - Justice dislikes nightmare very much because of the horrible actions he committed. Nightmare can't kill Justice and Justice can't kill Nightmare so instead they troll each other on Undernet and spam messages to each other like "I WILL SPAM YOU" and "WATCH THIS VIDEO" when actually the video ends up being the troll song. In fact they have actually had fun trolling each other and became friends.