(Hey, since this is currently the most viewed wiki page, I figure I'd just say please add actual information to the wiki instead of pissing all over it. Thanks.)
Zacharie is the game's item vendor, buying and selling items to and from The Batter. His shop is the only one in the game, and he often shows up in new areas or shortly before difficult fights. He has a tendency to frequently break the fourth wall, even more than the judge, often referring to the player directly upon speaking to him/her. He also refers to the player in a sign found in Bismark's shopping mall.
Zacharie is initially seen wearing a toad mask, which interestingly parallels a book found in the Bismark library that talks about a Masked Man who slays a Toad King. His neck also appears to be somewhat bloated and deformed, also resembling a toad, though this may just be speculation. He is later seen wearing a cat mask as a replacement for The Judge, who is put out of commission by the death of his brother Valerie. His talking sound also turns into a voiced "Meow" instead of his usual chuckle.
Zacharie is an item vendor, claiming himself to be "the traditional items merchant that's necessary in every video game", and he also may have a shop or shops located permanently in some places, as indicated by his sign in the Bismark shopping mall. He also may own the Bismark theme park, as there is a statue of him on the roller coaster, and an Elsen guarding an office refers to him as "boss".
He also seems to be a friend of The Judge, filling in for him and sometimes worrying for his safety. He is also a friend or accquantaince of Sugar, who requests that The Batter tell him goodbye upon her defeat. He appears saddened by her death, there is no chuckle when he is talked to. Interestingly enough, he states 'It's for the better'. It's possible that Zacharie resides in Zone 0 with Sugar and The Judge, and possibly Valerie in the past.
It's possible that Zacharie may be the Masked Man who slew the Toad King, or perhaps the story was based off of or even written by him.
Zacharie may have connections with Japhet or Vader Eloha, leading to his acquisition or creation of the Bismark theme park. It's possible that he may have built it without any necessary permissions, though.
Mortis Ghost has confirmed Zacharie to be a human.