Micah's gang is a faction in Red Dead Redemption 2. It is led by Micah Bell.
History
Background
After the Van der Linde gang's disbandment in 1899, Micah Bell (a former member) established his own outlaw gang, in which Cleet and Joe were a part of. The gang committed many crimes over the years, including robbery and murder - some of which involved dismemberment. In fact, Micah Bell alone was estimated to have killed around two dozen people while leading his gang. As a result, Micah and his gang became feared all over the frontier, with one newspaper saying that Bell's "acts of lawlessness rival that of Van der Linde himself".
At some stage, Micah led an assault on a homestead. During the raid, he killed an entire family - bar a little girl. Although Micah had wanted to kill her too, Cleet saved her from him.
Furious about the insubordination, Micah tried to kill Cleet, but he managed to escape. Additionally, Dutch van der Linde allied himself with the gang circa 1907, and helped Micah to retrieve the money in Blackwater from the ill-fated ferry robbery in 1899.
Events of Red Dead Redemption 2
Beecher's Hope Chapter
Sadie Adler informs John Marston that she has found Cleet, who is in Strawberry. With Charles Smith, they go and find him. The trio capture him at Strawberry, and proceed to beat him up, in order to get information on Micah's whereabouts. After Cleet denies knowing anything, they put him on the gallows, and threaten to hang him if he doesn’t talk. Cleet then cracks, and tells them that Micah is at Mount Hagen and that his gang are "bad men, doing bad things". Despite going on to tell them that he is "one of the good guys", Cleet is killed anyway - either from being hanged by John, or from being shot dead by Sadie.
Immediately after they arrive at Mount Hagen, Charles is shot in the right shoulder by a sniper. John and Sadie rush into cover and gradually move up in the mountain until the sniper is in range, where John manages to snipe him. They then go to see Charles, who insists they go on without him, and they do, grudgingly. As they advance up the mountain, two members of the gang ambush the two, with one of them stabbing Sadie in the stomach. Immediately afterwards, her attacker is shot in the back by Charles, while John continues subduing his opponent. Charles and Sadie, both severely injured, request that John avenge Arthur's death alone as they are incapable of doing so. John agrees, and treks up the mountain alone.
John is almost immediately confronted by Joe and two others. After a short exchange of words, John guns down all three in quick succession, before continuing his trek towards Micah. Eventually, John finds Micah and the two quickly end up in a shootout. Seemingly out of nowhere, Sadie flanks Micah from behind and holds him at gunpoin, forcing him to surrender. Before anything else can happen, Dutch exits a cabin to reveal himself, and aims his revolvers at Sadie and John.
With Sadie distracted, Micah quickly subdues her and holds her in front of him, while aiming a revolver at John. This results in a Mexican standoff between John, Micah and Dutch. John tries to convince Dutch that he always did his best for the gang and that killing him will "solve nothing". Ultimately, Dutch abruptly shoots Micah in the chest, mortally wounded him. Shocked, Micah stumbles backwards and then tries to shoot both John and Dutch, but John is quicker and shoots Micah repeatedly, finishing him off for good. Afterwards, John thanks Dutch for helping him, but Dutch invokes a glare and walks away without saying a word, consciously leaving the Blackwater money for the two. John then helps up the injured Sadie, and takes the Blackwater money from the cabin.
Aftermath
Soon after Bell's death, Bureau agents Edgar Ross and Archer Fordham show up on Mount Hagen, where they discover Micah's dead body. After a long manhunt for the culprit, they eventually trace Micah's murder back to John at Beecher's Hope.
Meanwhile, a newspaper reports that Micah Bell has been killed and that his "reign of terror" is over. It also speculates as to who had killed Micah, saying that he may have been "surprised by former gang members", and that the authorities are still searching.