Some people like to grab hold of someone and pound the fight right out of them. Grapplers can do standing locks or take people to the ground. In any case they try to render the people they fight helpless. Control is what their life is focused on. When things go awry a grappler tends to try and get them back into order as fast as possible. Most people have never dealt with a grappler and are surprised when they first encounter one, handing the grappler a huge advantage in a fight.
Clinch (Ex): Starting at 5th level a grappler's ability to control his grabbed foes is amazing. A grappler takes no penalties to his dexterity or attack rolls when grappling and is immune to the pin condition of being grappled. Add +1 to his CMB for grappling per three pugilist levels.
Ground and Pound (Ex): Starting at 10th level a grappler gains the ability to hold his foes and strike with ease. When a grappler has a foe grappled he can make a damage action as a swift action once per round.
Hinder (Ex): Starting at 20th level the grappler's restraint on a foe wears them out fast. At the end of the third consecutive round that a foe is grappled and every round after that, he must make a Fortitude save (DC = 10 + half the pugilist's level + Constitution modifier) or become fatigued. If the target is fatigued or fails a second save it then becomes exhausted.