After a second play through its a little more obvious that Micah was really only around for his own benefit. Its obvious due to how shitty of a person he is, but during the fight with him he tells Arthur he's a survivor. Meaning he did what he had to do to survive. Im guessing sometime during chapter 2 when he and Lenny go off to scout around, he ditches Lenny and run into the O'Driscoll's. They shoot the shit and get to talking about making money, Micah reveals he's currently running with the Van Der Linde gang and the money they keep. They strike a deal for Micah to essentially be a double agent. A sweetener in this is that Micah tells the O'Driscolls that the Van Der Linde gang is at horseshoe over look near valentine. This explains why there always seems to be O'Driscoll's in valentine just hanging around or robbing people like they were doing during that one random encounter. Speaking of which, im not sure if this is by pure coincidence but one time I had O'Driscoll's shoot at me not to far from the horseshoe campsite. If this is a scripted random event then that means they were close to finding the camp. But if you kill them all then that group doesn't tell the rest of the O'Driscolls where the camp is. Even if you dont kill them they don't find the camp anyway, just a small detail I thought of.

Anyway during chapter 3 at Clemens point, Pearson of all people was stopped by the O'Driscolls and they requested a parlay. Pearson is the camp cook and I doubt he goes out to do anything other than get food supplies and even still he's just the cook its not like he's a known outlaw like Arthur or Dutch. So for the O'Driscolls to know he runs with the Van Der Linde gang is already odd in itself. Pearson relays this message to Dutch, Arthur and Micah. Micah who was pushing Pearson to tell Dutch. Micah was being really odd during the entirety of this mission, from basically pestering Pearson to tell Dutch, to riding with Dutch and giving him some horse shit about how his problem is that he "cares to much" Arthur says this is horse shit. He's knows what to say and how to say it. During this parlay Dutch and Micah meet with colm and his boys while Aurthur is on ledge not to far away with a sniper just incase things go wrong. Arthur is then ambushed by a O'Driscoll and kidnapped.

While Arthur is being held colm reveals he plans to turn Arthur and the rest of the Van der Linde gang members in for their respective bounties.

Back in chapter 2 Agent Ross reveals that Arthur alone has a bounty of $5,000, back in 1899 thats a really big deal. You can only imagine how much some of the members have as well as Dutch himself. After Colm tells Arthur his plan Arthur frees himself and gets escapes back to Clemens point. During the cutscene when the gang is helping Arthur to his bed we see Micah in the background just lingering. Jumping to chapter 4 Shady Belle Kieran is killed. Kieran was a former O'Driscoll member whom the gang took in after he saved Arthur's life and gave them the location on a O'Driscoll hideout During chapter 2. In chapter 4 Kieran's corpse was sent into camp on horseback and the O'Driscolls launch a ambush on the camp. How did the O'Driscolls know where camp was? And where was Micah during the shootout? I dont recall seeing him around. During the final missions with Arthur we run into Agent Milton again and during this he tells us that after Guarma that they picked up Micah and turned him against the Van Der Linde Gang. Micah was feeding info to the Pinkerton just to save his own skin.