Masacre is a Spanish speaking man whom used to be a priest. He lived in Mexico and was saved by the original Deadpool once. After that, the man became idolized by Deadpool and wanted to become his Mexican counterpart. He made himself a Deadpool-themed outfit and started calling himself Masacre.
Masacre was created by Gerry Duggan, Brian Posehn and Scott Koblish and first appeared in Deadpool #3.1 (2016), which was an official American Marvel comic-book, but completely written in Spanish! Some months later, a translated (English) version of the comic was published for "all those Marvelites that didn't speak Spanish".
Fun fact is that the character Deadpool is named Masacre in Marvel comics translated into Spanish.
Major Story Arcs
With the Mercs
While Masacre was working as the Mexican Deadpool, he was soon recruited by the real Deadpool to join his team of mercenaries. Masacre agreed and became part of a team known as the Mercs for Money. Due to his total failure of the English languague, Masacre is not understood by his teammates and often vice-versa.