The Mennointe was created by Jason Aaron and Steve Dillon.
The Mennonite refuses to reveal his full name. It is hinted but not not revealed for certain that his religious affiliation did not always effect 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 were brought to the U.S. by William Penn and settled mainly in Pennsylvania. There 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 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 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 weaponery, but chose to attack Castle with a sledgehammer. It makes it fitting that resorting to modern weaponery was his downfall.