Aradesh is a good man who's genuinely concerned about his people and their problems. He may be a bit suspicious of the Vault Dweller at first, and can seem a bit paranoid, but that's because he distrusts all outsiders. It is possible to earn his trust.
Aradesh was originally a Vault 15 dweller, a sister vault of Vault 13. His accent and appearance are attributed to living in Vault 15, which housed the social experiment of incorporating people of diverse cultural backgrounds.
However, Aradesh left the vault with the other dwellers following a disastrous attack by raiders. Along with a few other exiled inhabitants of the vault, he ventured out into the wastes, looking for a place to begin anew.
Soon after the attack, Aradesh founded the humble community of Shady Sands using a G.E.C.K. in 2142. He then led the community with a steady, guiding hand, reinforcing the slightly xenophobic attitudes of the townsfolk, aiming to make it a completely self-sufficient community, and keep it that way. Initially, he greeted the Vault Dweller with reserve, but after they removed the radscorpion threat and later saved his daughter from the Khans, he welcomed them openly in the community. Broad horizons were opening up for the small town.
Aradesh (along with Seth and Tandi), would later start laying the foundations for the New California Republic, with him being elected as its first president. Soon after, inspired by the Vault Dweller's legacy, Aradesh and Seth began searching for Vault 13. However, during one of their expeditions they disappeared and were proclaimed dead. Afterwards, his daughter took her father's position of President, guiding the NCR to a brighter, safer future.
He is likely to be among the first non-player characters with a talking head that are encountered. It will be learned quickly that he does not tolerate being lied to. Should the Vault Dweller act rash, refuse to answer questions, or lie about their origins in Vault 13 (excusing the fact that with a high Speech skill it is possible to lie one's way in), Aradesh has no qualms about leading them back to the town borders. This has no real effect on further interactions in the town, as one can return and re-initiate dialogue with Aradesh without negative repercussions.