Arroyo is a tribal village, founded by The Vault Dweller after his adventures in the wastes. The village is made up of Vault 13 residents who left the vault in order to follow in the footsteps of the dweller, they were also joined by stragglers along the way to the location of where Arroyo would be built.
Arroyo is located in north-western California, and has a natural defensive position as it is very hard to access, being that it's located in a canyon.
Arroyo was founded by the Vault Dweller after he was exiled from his home, Vault 13. During his wandering through the wastes, he came upon a group of Vault 13 inhabitants, who inspired by his deeds, left the vault. The small group had a very limited knowledge of the outside world, and they surely would have perished had it not been for the Vault Dweller. He took of his vault suit, never to wear it again, and led the small group of former vault inhabitants, along with some wanderers they picked up along the way, north.
There they settled, the Vault Dweller fell in love with a tribewoman named Pat, and together they formed a family. The construction of Arroyo was finished on August 18, 2167. The Vault Dweller eventually disappeared from Arroyo, leaving only his old Vault Suit. Some of the tribal people thought that the great Sky spirits have taken him.
The Vault Dweller, now a leader of the small tribe and village of Arroyo, had two children with Pat, the girl who would become Elder, was born in 2208 and Morlis. The girl born in 2208 would grow up to become the village elder, and her son, the grandson of the Vault Dweller would become The Chosen One, after his successful trial in the temple.
In 2241 (the beginning year of Fallout 2) Arroyo was experiencing the worst drought they had seen, as well as disease. The village elder had read an advertisement describing the "holy" Garden of Eden Creation Kit (G.E.C.K). She decided that the only way the village could be saved was if she sent her son to find it. He was tasked with passing the Temple of Trials. After successful completion, the Elder's son became The Chosen One, and he was sent out into the world in search of the G.E.C.K.
Sometime during his search, Arroyo fell under attack from a mysterious faction known as The Enclave. The Chosen One returns to Arroyo, only to find that the village had been destroyed, as well as the bridge leading into the village. The only survivor of the attack was the village shaman, Hakunin, who tells the Chosen One what had transpired. The Enclave attacked, either killing the tribal warriors, or capturing those who couldn't or wouldn't fight. Eventually, The Chosen One defeats the Enclave, by destroying their headquarters which is located on an Oil Rig in the ocean, near the California shoreline. The Chosen One rescues his tribe, as well as the captured Vault 13 residents. The two groups return to Arroyo, and rebuild it using the G.E.C.K. and the Vault 13 dwellers scientific skills coupled with the tribal's survival skills. The village Elder dies quietly in her sleep. The Chosen One becomes the Elder and rules the village of New Arroyo, which prospers under his wise rule.
Arroyo is a small tribal village, as such most of the residents either toil the land or hunt the various wild life. They have no army to speak of, and should the village be attacked, hunters band together to defend it. Although brave and skilled with their spears, their courage would prove of little use against more powerful opponents...wearing power armor.
Apart form the Village Elder and the shaman, there are no other notable positions. The Elder has the most power, but the 3 known elders of Arroyo didn't seem to usurp it.
The villagers are descendants of Vault 13 residents who followed the Vault Dweller. The tribe seems to revere him, as well as Vault 13, as almost holy things, creating a quasi-religion based on them.
Just north of the village is the Temple of Trials, where candidates go in difficult times to prove themselves. Other than that, in the north eastern part of the village, there is some tilled land, in the central part is the residential area, and in the very center of the village is a giant head. It seems to be a statue commemorating the vault dweller. Towards the west are the wilds, where hunters presumably hunt geckos for their meat and pelts. And to the south there is a bridge that allows the villagers to travel to other locations.
The Vault Dweller - Protagonist of Fallout, the founder of Arroyo and the first Village Elder. He is the father of the Elder that appears in Fallout 2, as well as the grandfather of The Chosen One. He was married to Pat, and several years after her death, he simply vanishes.
Village Elder - The Vault Dweller's daughter and Chosen One's mother. She was prepared for a greater portion of her adolescence for becoming the village elder. She is wise and just, although not particularly well educated, as she refers to the G.E.C.K. as holy, and similarly calls the original vault "the holy Vault 13".
The Chosen One - Vault Dweller's grandson, and the Elder's son. He saved Arroyo, or rather, rebuilt it using a G.E.C.K. He also freed the captured Vault 13 residents and his fellow tribals from the hands of the enclave. He would eventually become the Elder after his mothers death.
Hakunin - The village shaman. He speaks in a unusual manner, and many of Arroyo's residents find him weird and eccentric. He still takes care of the villagers, and being a shaman, has a very close relationship with nature, or what's left of it. He can communicate with the Chosen One through dreams, and thus, warns him each time the situation in Arroyo grows more dire. Hakunin is regrettably killed at the hands of the Enclave.
Morlis - The Chosen One's aunt, and second daughter of The Chosen One. She is a bitter and stingy woman, and has a great dislike for her nephew, perhaps because his mother is village elder.
Nagor - The Chosen One's cousin, Morlis's son.
Feargus - Chosen One's nephew.