Niles was an employee of Teenage Mutant Ninja Turtles III villain Walker. He was unskilled in combat and only had basic firearm capabilities. Niles had quite an unpleasant personality; he constantly would taunt and berate others (for example, calling the prison warden "Fatso-San"), and attempted to force a kiss from April.
The Turtles constantly tormented him with "wet willies" and at one point, to save himself from theirs, he applied them to himself.
Teenage Mutant Ninja Turtles III