The name Knifeketeer is, of course, a play on the term Musketeer, which was a person who fought his enemy with muskets.
There were also Grenadiers, who fought their enemies with grenades.
I could have named him the Knifier, but to me that seems similar to a sommelier, a person who, rather than fighting his or her enemies with wine, simply knows everything about wine and shares that knowledge with anyone within earshot.
Actually, The Knifier would make a good enemy for the Knifeketeer. The Knifeketeer would attack the Knifier with a knife, and the Knifier would criticize his blade choice.
“A bowie knife? In September? Don’t you think an imported Japanese tanto would be more appropriate?”
The Knifeketeer would HATE that.