The Mennonite was created by Jason Aaron and Steve Dillon.
The Mennonite refuses to reveal his full name. It is hinted but not revealed for certain that his religious affiliation did not always affect his business methods as when he arrives in Mennonite garb and refuses to accept a gun, his bosses seem surprised as if he had previously been known to use them.
The Mennonites are a branch of Christianity that was brought to the U.S. by William Penn and settled mainly in Pennsylvania. Their trademarks are non-violence and not using electricity, similar to the Amish people. The Mennonite obviously disregards the non-violence rule, as he is an infamous assassin who used very brutal methods and once worked for Don Rigoletto.
He started to kill again when needed money to cure his dying wife and raise his two children. His wife needed an advanced medical cure that Mennonites couldn't provide so he returned to Rigoletto for one job, to kill Castle.
The Mennonite starts in on Castle with a sledgehammer but is very resourceful; going so far as to use his own horse-drawn carriage as a weapon; whistling to his horses to get them to trample Castle.
Skills and Weapons
He is a vicious fighter with the willpower to drive him every bit as determined as Frank Castle. The two are pretty much evenly matched.
The Mennonite was able to withstand a great deal of damage in his fight with Castle. This includes being beaten, being kicked in the groin with a shoe knife, and being blown up (with his horse and buggy absorbing some of the explosion) by a trap left by Castle. After all this he was still able to defeat Castle in a fight, however, he attempted to use one of Castle's guns to finish him off. Castle had electrified his weapons and the Mennonite was electrocuted. Castle then finished him off by dropping a safe on his head.
It seems that in the past the Mennonite was willing to use modern weaponry, but chose to attack Castle with a sledgehammer. It makes it fitting that resorting to modern weaponry was his downfall.
In Other Media
The Punisher (Netflix)
The Mennonite appears in the second season of the Punisher as an antagonist. Although he is never called the Mennonite, it is clear that the character John Pilgrim in the show's version of the Mennonite. Like the Mennonite, Pilgrim is a retired assassin who decides to return to his old ways because he needed to get the money to treat his dying wife and raise his two sons. Where Pilgrim differs from his comic book counterpart is that he is willing to use modern weapons like guns something the Mennonite refused to do.
Pilgrim is summoned by Anderson and Eliza Schultz to prevent the public from learning that their son Senator David Schultz is gay. His job is to kill anyone that knows and destroy the photographic evidence of David's homosexual relationship. When he learns that Amy Bendix has the photos of David he recruits ex-veterans to help him capture and kill her and destroy the photos. However, the Punisher saves Amy and thwarts his scheme. This gives Pilgrim a new objective to kill the Punisher. Meanwhile, Pilgrim's wife dies and the Schultz's hold his sons hostage until he completes his mission. He first puts out a bounty on Frank and Amy, when that fails he decides to take care of the Punisher himself. When the Punisher is in the hospital after being severely wounded from his encounter with Jigsaw, Pilgrim goes to the hospital to kill the Punisher. However, the Punisher escapes, but Pilgrim does discover where the Punisher is camped out by steeling Agent Medani's car. Pilgrim attacks Curtis looking for Frank and Amy. Meanwhile, the Punisher interrogates David Schultz in hoping to figure out what Pilgrim is after. Frank kidnaps David and uses him as leverage against his parents. However, Amy hid the back of Pilgrim's car and this leads the Punisher to Pilgrim's hideout. The two end up in a shootout and Pilgrim capture Amy in the confusion. Then they go to the trailer where Frank was camped out in NY and fight. The Punisher wins and before he could kill Pilgrim, Pilgrim begs him to spare him and let him be with his sons. The punisher agrees to spare him and kills Anderson and Eliza Schultz freeing Pilgrim's sons.