Javier Escuella was born in Nuevo Paraiso and was once a Mexican revolutionary. According to Colonel Allende, Javier's father was a drunk that worked on his uncle's land.
After spending some time in America, Escuella became a member of Dutch's Gang. When Dutch's gang was disbanded after Dutch went insane, Javier took it hard and returned to Mexico to work as a hitman for Allende. Marston is forced to pursue him in 1911 by the federal agents.
Even though he is a central character, Javier Escuella only appears in one mission and doesn't have much of his backstory revealed compared to Bill and Dutch.
Prior to John's assault of Fort Mercer, Javier helps Bill to escape to Nuevo Paraiso. When John Marston hunts him down throughout Mexico, Javier takes refuge throughout the countryside in various forts, staying reclusive. After Allende's betrayal, Javier is eventually caught by John, who has help from Abraham Reyes. Javier has been hiding in a fort surrounded by his fellow henchmen, but John breaks in with the help of rebel friends and the two confront each other in a storage closet. John then holding Javier at gunpoint.
The two have a conversation with each other, with Javier slowly inching his way over to John. Javier waits until John is distracted, and then he pushes a crate on John. Given some time, he jumps out a nearby window and onto a deck. Javier calls out to John, saying he was "always the weakest" and then rides out of the fort with a horse. John runs after him, and then the player can do one of two things:
Kill Escuella. If the player chooses this, John guns down Javier while riding his horse. John then takes his dead body and puts it in a jail cell, because he has to show it to Edgar Ross and Archer Fordham as proof. Before walking out of the jail cell though, John looks at his old friend lying dead on the floor and wipes a tear from his eye and then spits on his corpse. Later on, John takes Javier's dead body to the government agents (Fordham will then say: "I expected him a little more....healthy") and Javier's dead body is taken away.
Or, John can capture Escuella by shooting his horse and lassoing him, or just lassoing him. John takes a struggling Escuella to a jail cell and then heads off the next morning with Escuella on the back of his horse. Before turning Escuella into the government agents, Javier spits on his arm and calls John a puto (Bitch). Javier is taken away and is not seen for the rest of the game. It is mentioned later in the story by John that he is deceased in a conversation with Abigail.
In "The Gates of El Presidio", if the player captures Escuella, he will ask John "What about your wife and children?". This gives a time frame to Marston's daughter's death, implying that she died after John left the gang.
Hogtying Escuella, sticking him in front of the gate, and then using the Cannon to blow him up will have the same effect as turning him in alive.
Javier calls John his "brother" quite often, implying that they were close friends. Further evidence for this friendship is when John bursts into his hiding place, rather than kill John while he's distracted, he runs out of the window.
Javier has a knife holster, but he does not have a knife. The player can see the knife holster if he kills Escuella. This may be the reason why Javier is inspecting a Knife in Multiplayer.
His sombrero is the same sombrero as the Bandito Outfit's, only that Javier's is a bit bigger while Bandito Outfit is smaller.
His last name "Escuella" is closely related to "school" in Spanish (Escuela). On the other hand, "escollo", which sounds a little alike, has different meanings, like: pitfall, stumbling block, reef, rock, barrier, hidden danger. A mixture of "escuela" and "escollo" could mean that Escuella was really one of the many obstacles Marston has to endure to get his family back.
In the Chuparosa saloon there is a picture on the wall near the table where Banditos can be seen drinking, the man on the picture is possibly Escuella.
Judging from the way Marston and Escuella's confrontation was going, Javier possibly could have talked John out of taking him into custody if he hadn't attacked John and tried to run.
Javier's death is seemingly confirmed in the mission "Old Friends, New Problems" where John tells Abigail "Bill, Javier, Dutch. They're all dead. It don't get more over than that." Despite the fact that John can spare Javier, John still says this line. Meaning that he was indeed executed after being captured by John.
In "The Demon Drink" Allende mentions being somewhat associated with Javier's father by saying "Escuella is from this province. His father was a borracho, a drunk who worked as a laborer on land cultivated by my uncle."
Escuella will be wearing either copper or rusty iron cuffs if the player hogties him.
According to John, Escuella never attempted to teach John or his fellow gang members any Spanish, something Abraham Reyes sneers at.