Anton Krug is Sean Renards cousin.
As Thomas Woosley holds Renard at gunpoint to meet his cousin, Anton tells Remard why things aren't moving as they should be. He then says, the family will either have Renard give them the key, or they will take the Grimm and find the key themselves. He wants answers and action. Renard shakes his head and says okay, but he does do action, not the way Anton meant though, as Renard knocks Woosley down, takes the gun out of his hand, and shoots and kills Anton with a bullet to the head. Renard, after killing Woosley, puts the gun in Anton's hand, and fores a ahot to put powder burns on Anton. The death of Woosley and Anton turns to a double homicie investigated by Nick, Hank, Wu, and to some extent, Remard himself. They don't catch a killer, as Renard did such a good job making it look like they killed each other, the investigation is called off.